Skip to main content

Full text of "The geology of the Whangaroa subdivision, Hokianga division"

Digitized by the Internet Archive 
in 2013 



http://archive.org/details/geologyofwhangarOObell 



To iicfxntitunyHtiUi tin jV.^' S. Wzimt/itn a SubdU'isU/nJIcktamfaDn'isicn .Aucklandland District 








JAMES MACKINTOSH BELL 



^P~ > i?-\ N yt^^\K/ I T ^/B R B 



GEOLOGICAL MAP OF 



/toads sittnvn, litus. 

Tracks „-- 

jyaniLines „ ..-- 

Edges of BusK.. ,. .,-. 

Swamp - ,, .1 - 

Old Muvrl Pat 



Trig. SUiUons — shotvn, t/ius. . 

WalerfaUs „ „- - 

Mine fVbrkings „ „-- 

:lui,y>, thus 



OtUcropn wUK observed, strike and. dip > 



-Scaic ofChai 



SEDIMENTARY ROCKS 



Reference to Geological colours 



I Wa'papa Series — 
> lArgiNues, grauwackes, quartiitesfc I 
'and contemporaneous iSneous rochs._l 



EARLY TERTIARY \^onyeUun3TY snaies. craysconcs. ^^^- 
Isandslones, ^rccnsands ana Itmestones-l^ 



N^'awha Lake Beds- \ 

iGms and «rbonDCeou8 sands Sdayd 

H.^h- level terraces- 
:Gra«ets, sands and muds. ' 

I Spring, fh^'at.lejacustr.nesnd 

Fluv'O-manne depo^.ts- 
(Sinters, gravels and silts 



3CENE0H t Ker.ker. Senes.- 
r-MtOCENE (Dolerrtic and andesit.c flows. __ 
( Acidic and later basic vo/canic 
-MIOCENE JR^,y(,,,^|(. a„j basaltic flows. 



Cnnabar dcpcs, 
Fault-lines 



:[zz3 



Tci uccMTnjjariyBulUttnNS8yntanqcuroaSTihdwision,nokiaTi€ja.Dimswn..Aucklantl,Land District 




PLAN OF 

PUPUKE COPPER FIELD 

KAEO SURVEY DISTRICT 

Scale of Cliain> 



Org^'. by O.A Darby . Mire^'OA 



Bu Authority : John Maohay. Qoutrnmant Mitttr. 




K A® \w A K A 



-SEFERENCE- 



Roads — tf=^5- 

Tri^. Stations ©oro 



Bush ■QZ^ 

Mangrove Stramp_ -&%*« 
. /Isupo i other., »♦ t. 



"4 /< E R I "K E R I 

TOPOGRAPHICAL MAP OF 

WHANGAROA SUBDIVISIOI 



W H A K A R A R A 



To acccmpcuxy BulUtinlf-^ ft 




To accompany Bulletirhl^'9 8 




Mt AMtk^lt^ : Jthn ItAokmy. Q*Mj^mvit f/ 



To (xccompany Bulletin N^ S 



MAP OF 



NCAWHA LAKE BASIN 

OMAPERE SURVEY DISTRICT 

Scale of Cliailis 




'■^<i!Mi>'' If/ ■.^Pjr^M.gHole-' Shaft ^■''jrf.fe'l ■\^/Aai>'«)m.S''",'i'"»"''Afe 






OMAPERE S.D. 



#9 



r.^' 

^^^ 










PUNAKITERE S. 0. 






JAMES MACKINTOSH BELL 



ComyUed from, surveys iy E.deC.Ctaj-ke 
txjui from^ sketch, plan, hy AT 0-rL/fi,ths. 



w 



f soiaitiiny xTtoi^n. ttuu « 



Dra^iLiy 0-AJ)arhy Mar 



«V XxttM-Jt* .- ^sAn lr«elia«. «wMn)nMt / 



To uccvm|JUn.y'Bu.lUtinNSS^V),an<fart.a.Subdi»■iswnMoha^l^^aVi^'lSwn.Allcldlmd Land District 



GEOLOGICAL SECTIONS 

WHANCAROA SUBDIVISION 



Natural Scale 




Section along Line ABC, (Middle Portion Kaeo S.D.) 




of Walpap. 



Section along Line DE, Whangaroa and Kaeo S.D^ 





Section along Line HIJ, Kaeo and Omapere S.D^ 
REFERENCE TO GEOLOGICAL COLOURS 



SEDIMEMTARV ROCKS 



IGNEOUS ROCKS 



JAMES MACKINTOSH BELL 



Otsyyn by OADarby, Apr,/ IS03. 



IWaipapa Series. - 
Argill,fes,grauwacke6,<]uartzlte6 c 

Haeo Series. - 
LATE MESOZOIca Conglomerates, tuffs, concretjonai 
EARLY TERTIARY shales, claystones, sandstones, 

greensands and limestones. 



iN^awha La. 
e{ Grits and cai 



.al<e Beds - 
POST-MIOCENE^ Grits and carbonaceous 

{ sande and clays. 

fSprinp.fluviati/e, lacustrine 
and thvio-manne deposits; 
Sinters, gravels and sifts. 



POST-WAIPAPA AND 
PROBABLY POST-KAEO 



YOUNGER THAN 
THE ABOVE 



Basic and Semi- basic intrusives - \ 
Andesites. diabases, diorites j 

L 
Semi- basic pvrodastics, 
flows and dykesr 
Andesites and dolerttcs. 



^ 



iWa'irahau Serlei 
Andesitic brecc 
tuffs, Jylies if lo. 



»,iu..t,.tvr> j,„|j„^,c and 
POST-MIOCENE [andesitic flows. 




'R> aca>mpLuiyBulletinI^S.Whanqairt<tSu2>diyUwn^a)aan^aJ)wLsiB^ 



GEOLOGICAL MAP OF 




- Reference to Coloi 



^^ 



Sprinat % 

Outtnpi Yiilh ciririid- ilip anil ttrUieA 



CtOUfi ArSIMIl.) J-n 




X22n 






\\^ h a n g a r o a 



s f 







^3^„.„..A^: 










MdAI}! ().)«>[ |o iniu>l\l 

luisuuariSuintiv 



ta 

CO 

a'. 

C 




uSuuuH 






department /oy<^W^^ni of ^^tines. 



NEW ZEALAND GEOLOGICAL 8UKVEY. 

(J. M. BELL, Director.! ^\(^^ 



BULLETIN No. 8 (NEW Series). 



THE GEOLOGY 



WHANGAROA SUBDIVISION, 



HOKIANGA DIVISION. 



J. M. BELL AND E. DE C. CLAEKE. 



ISSUED UNDER THE AUTHORITY OF THE HON. R. McKENZIE. MINISTER OV MINES, 




NEW ZEALAND. 
BY AUTHORITY : JOHN MACKAY, GOVERNMENT PRINTER, WELLINGTON 

1909. 



LETTEE OF TRANSMITTAL 



Geological Survey Office, 

Wellington, 4th October, 1909. 
Sir, — 

I have the honour to submit herewith Bulletin No. 8 of the 

New Zealand Geological Survey. 

It contains the results of the work conducted by Mr. B. de C. 
Clarke, Assistant Geologist, and myself in the Whangaroa Subdivision 
of the Hokianga Division, North Auckland, during the field seasons of 
1907-8. 

The bulletin is accompanied by eight maps and one sheet of 
sections, and is illustrated by seventeen plates. 

I have the honour to be, 
Sir, 
Your obedient servant, 

J. M. BELL, 

Director, N.Z. Geological Survey. 
Hon. K. McKenzie, 

Minister of Mines, 

Wellington. 



PREFACE, 



The field work in the Whangaroa Subdivision, with which the present bulletin 
deals, extended over a period of fourteen months, from August, 1907, to 
October, 1908. During this time Mr. Clarke was almost continuously in the 
field. As I was able to spend only about two months with my collaborator, 
my share of the field work was small. All the stratigraphy, the geology of 
the igneous rocks, and the whole of the topography are the result of Mr. 
Clarke's careful work, and he is almost entirely responsible for Chapters II, 
IV, and V. 

With Mr. Clarke's assistance I studied at various times all the principal 
deposits of economic interest. In the bulletin. Chapters III and VI have 
been written mainly by me, while Chapter I was prepared by us conjointly. 

We are nmch indebted to many persons in the area for assistance and 
information received during the course of our work, and we wish especially 
to thank Mr. J. Hare, of Kaeo, and Mr. T. M. Lane, of Totara North. We also 
wish to express our indebtedness to Messrs. T. F. Cheeseman, of the Auckland 
Museum, and Augustus Hamilton, of the Dominion Museum, Wellington ; 
and to Professors A. P. W. Thomas, of Auckland University College, H. B. 
Kirk, of Victoria College, Wellington, and P. Marshall, of Otago University, 
Dunedin. 

All the analyses in the bulletin, unless otherwise stated, are the work of 
the Dominion Analyst, Dr. J. S. Maclaurin, and his Staff. 

J. M. BELL, 
Director, N.Z. Geological Survey. 



CONTENTS. 



Letter of Transmittal 
Pkeface 



111 

V 



Chapter I. — General Information. 



Litroduction 

Economic Reasons for Work in Hokianga 

Division 
Area described in this Bulletin 
Plan of conducting Work 
Fauna 
Flora . . 
Timber and Flax 



Page 
..1 


Soil and Agriculture 


Page 
6 


Hokianga 

-.2 
.. 2 


Climate 

Scenery 
Literature 


. 10 
. 11 
. 12 


.. 2 
..2 


Population and Early History 
Industries 


. 15 
. 13 


..3 


Means of Commuuioation 


17 


6 


History of Mining 


. 17 



Sequence of Formations. 
Gieologioal History 



Chapter II. — Odtline of Geology. 

. . 20 I General Account of the Structure of the 
. . 21 I Several Formatioius 



22 



Chapter III. — Physiography. 



Introduction 
The Land 

(a.) The Faulto-d Tableland 

(6.) Re.sidual Hills or Moiiadnooks rising 

above the ijovol of the Faulted 

Tabl(^land 
(f.) Isolated Hills of Wairakau, Kerikeri, 

and Later Acid Volcanics rising 

above the ( ioneral Level of the 

Faulted Tableland 
{d.) Cones of the Ijater Basic A'olcanics 

near Like Omapere 



24 
25 
25 



27 



27 



The Land — continued.' 

(e.) Plains of Different Origin from the 
Faiiltetl 'lablolaud 

{/.) Low-lying Alluvial Flats 
The Shore-lino 
The Drainage-channels 
Fresh-water Basins 
Swamps 
S] (rings 

(a.) Soda S])ring8 

(b.) Sulphur Springs 
Man's Influencte on the Physical Features 



28 
28 
29 
32 
33 
31) 
30 
36 
37 
40 



Chapter IV 


— T 


The Waipapa Series 






41 


(a.) Introductory 






41 


(6.) General Distribution 






41 


(c ) Structure 






42 


(d.) Petrology 






43 


Argillites 






43 


Grauwackes 






44 


Quartziten 






44 


Friction Breccias 






44 


Schi.sto.se Rocks 






44 


Marble 






45 


(e.) Mineralisation 






45 


(/.) Correlation and Age 






45 


The Kiieo Series 






46 


(a.) Introductory 






46 


(6.) General Distribution 






46 


(r.) Structure, Distribution, a 


nd 


Inter- 




relationships of the 


Different 




Members of the Series . 




, . 


47 


Conglomerates . . 


. 


, , 


47 


Tuffs .. 






48 


Concretionary Shales, ( 


^aystones, 




Sandstones, and Shal 


y 


Im])ure 




Limestones . . 






48 


Massive Limestones 






48 


Greensands and Clayston 


es 


, . 


49 


Calcareous Sandstones . 


. 


. , 


49 



The Stratified Rocks. 

The Kiveo Series — continued. 

(d.) Petrology .. .. ..49 

Conglomerates . . . , . . 49 

Tuffs . . . . . . .50 

Concretionary Shalas, Claystones, 
Sandstones, and Shaly Impure 
Limestones . . . . . . 51 

Massive Limestones . . 53 

Greensands . . . . . . 54 

Calcareous Sandstones . . . . 55 

(e. ) Palaeontology . . . . . . 55 

Fo-ssils of the Concretionary Shales 

and Sandstones . . • . . 56 • 

Fossils of the (ireensands . . 57 

(/. ) Correliktion and Age .. .. .58 

Xgawha Like Beds . . . . . . 58 

High-level River Terraces . . . . 59 

Recent De])osit8 . . . . . . 60 

(a.) Hot and Cold Spring Deposits . . 60 

(6.) Fluviatile De]>08it8 .. ..61 

(1.) Alluvial Flats ..61 

(2.) Swamps . . .. ..62 

(c.) Lacustrine Dejtosits . . . . 62 

(d.) Fluvio-marine and Marine Deposits. . 62 
( 1 . ) Estiiarine Dejwsits (Tidal Flats) 62 
(2.) Sand and other Marine De- 
tritus .. .. ..62 



Vlll 



Chapter V. — Igkeous Rocks. 



Introductory . . 

1. Contemporaneous Igneous Rocks of the 

Waipapa Series . . 
(a.) Structure and Distribution 
(6.) Petrology 

2. The Wairakau Series . . 

(a. ) Structure and Distribution 

(b.) Petrology 

(c.) Secondary Siliceous Deposits 

(d. ) Correlation and Age 

(e.) Conditions and Foci of Eruption 

3. The Kerikeri Series . . 

(a.) Structure and Distribution 
(6.) Petrology 

(c.) Local Aqueous Deposits 
(d. ) Correlation and Age 



Page 
63 

63 
63 
64 
65 
65 
66 
68 
68 
69 
69 
69 
70 
71 
72 



3. The Kerikeri Series — continued. 

(e.) Conditions and Foci of Eruption. . 

4. Acidic Igneous Rocks 

(a. ) Structure and Distribution 
(6. ) Petrology 

5. Later Basic Volcanics 

(a.) Structure and Distribution 
(b.) Petrology 

6. Igneous Rocks of Doubtful Age 

(a.) Igneous Rocks, either Wairakau or 

Keiikeri in Age 
(6.) Igneous Rocks, Post- Waipapa and 

probably Post-Kaeo in Age 
(c.) Igneous Rocks younger than those 

of the preceding Section 



Page 



72 

72 
72 
73 
74 
74 
74 



76 



78 



Chapter VL — Ecosomic Geology. 



Introduction 

Cupriferous Sulphide-ores 

Ores of Mercury 

Occurrences of the Precious Metal; 

deposits and Quartz Veins 
Iron-ore 
Oxides of Manganese 





80 


Coal .. 




80 


Kauri-gum 


. . 


87 


Mineral Oil 


Is in Sinter- 




Building and Cement Stones 




92 


Mineral Waters 




93 


Sulphur 




94 





95 
96 
96 
97 
97 
98 



Appendix A. — List of Minerals found in the Wbangaroa Subdivision, ilode of Occurrence, &c. . . 99 

Appendix B. — Glossary of Scientific and Mining Terms used in this Bulletin . . . . . , 100 

Index .. .. .. .. .. .. .. .. •■ .. -.107 



LIST OF ILLQSTRATIONS. 



Plate. 

I. Head of Whangaroii Harbour 
II. Kauri Bush 

III. Looking South-west from Orotere 
" Mixed Bush " on Slojies of Maungaeraiemi Hill 

IV. Lake Omapere from Western Side 
View of Putahi Hill across Lake Omapere 

V. Utakura Falls, on the Utakura River . . 
nood-plain of Waitangi River 

VI. Head of Whangaroa Harbour at Low Tide 
VVhangaroa Townsliip and St. Paul's . . 

Vn. Coast near Mahinepua Bay at High Tide 
Shoreline of Flat Island 

VIII. Taupo Bay at Low Tide 

Waihi Bay, UTiangaroa Harbour 

IX. View of Okamoko Bay from Shark Island 

X. Lower Part of Whangaroa Harbour from the Slopes of St. Paul's 
Head of Whangaroa Harbour from the Slo]>es of St. Paul' 

XI. Micro-photographs of Waipapa and Kaeo Rooks 

XII. Fos,sils of the Kaeo Series 
X IIT. Micro-photogTa|>hs of Kaeo, Wairakau, and Kerikeri Rocks 
XrV. Micro-jihotographs of Kerikeri and Later Volcanics 

XV. Micro-photographs of Later Basic Volcanics and Igneous Rocks <>f,(Doul)tful 

XVI. Entrance to Hare and Ratjen's No. 2 Drive, Pupuke Copperfield 
Area Xo. .5, Ohaeawai Hot Springs 

XVII. Area No. 5, Ohaeawai Hot Springs . . .... 

Reduction- works, Ohaeawai Hot Springs 



Age 



Facing p<age 

Frontispiece. 

2 

) 



16 

24 

30 

.32 

36 

40 

43 
56 
66 
70 
74 

83 
92 



MAPS 



1. Map of New Zeikland, showing Land Districts and Divisions. 

2. Map of Hokianga Division, showing Survey Districts and Area geologically surveyed. 

3. Geological Map of Whangaroa and Kaeo Survey Districta. 

4. (Jeological Map of Omapere Survey District. 

5. Topographical .Map of Wliangaroa Subdivision. 

6. Map of Wliangaroa Harbour. 

7. Plan of Pupuke Cojiiierfield. 

8. Map of Ngawha Ijake Basin. 



GEOLOGICAL SECTIONS. 



1. Section along Line ABC, Whangaroa, Kaeo, and Oma])ere Survey Districts. 

2. Section along Line DE, Whangaroa and Kaeo Survey Districts. 

3. Section along Line FG, Kaeo Survey District. 

4. Section along Line HIJ, Kaeo and Omapere Survey Districts. 



if — W hangaroa. 



ADDENDA. 



On all maps except Omaptre Survey District and Ngairha Lake Basin: " Compiled 
from data obtained from the Lands and Survey Department, and additional surveys by 
E. de C. Clarke, of the Geological Survey Branch of the Mines Department." 

Also, on map of Whnngaroa Harbour : " and from data obtained from Admiralty 
Chart." 




8000.^03.318 



By Authcrity : John Uackay, GovtmnutU Frinttr. 



To cLccompouvy Bulletin. 2^S 8 



NORTH CAPE 



REINCA 



MURIWHENUA 
WEST 



SOUTH PACIFIC 



O C E A If 



JAMES MACKINTOSH BELL 
DIHCCTOR 






q.Ef^. 




T A S M A N 



SEA 



MAP OF 

HOKIANGA DIVISION 

SHOWING SURVEY DISTRICTS 

Ufitru-ta fJeuU wUh U hBiMe tin. N^ S 
cohnired thxts I I 



10 5 O 

'-' l-l "-I 1-^ l-l l-^ 



ENGLISH MILES 
10 



NORTH HEAD 
Kill para Harboui- 



Sy f^uX^>9rit^ : John tlmoltay, Qcmrnmtnt ^rimttr. 



1600.4/09.288 



BULLETIN No. 8 (NEW SERIES) 



THE GEOLOGY 



OF THE 



WHANGAROA SUBDIVISION 

HOKIANGA DIVISION. 



CHAl'TEK 1. 



GENERAL INFORMATION. 



Page 




Page 


Introduction . . . . . . 1 


Soil and Agriculture 


. 6 


Economic Reasons for Work in Uokiunga 


Climate 


. 10 


Division . . . . . . 2 


Scenery 


. 11 


Area described in this Bulletin . . 2 


Literature 


. 12 


Plan of conducting Work . . . . 2 


Poj)ulation and Early History 


. 15 


Fauna . . . . . . . . 2 


Industries . . 


. 15 


Flora . . . . . . . . 3 


Means of Communication 


. 17 


Timber and Flax . . . . . . 6 


History of Mining . . 


. 17 



Intkodiction. 
The Hokianga Division forms the most northern part of the mainland of the North Island of 
New Zealand. The division lies between latitudes 34° 23' and 36° 25' S., and longitudes 
172° 38' and 174° 7' E. 

The division is of irregular outline. Its south-western boundary is formed by the long, 
gently-curving shore-line, which stretches from the rocky island at Cape Maria van Diemen 
to the sand-dunes bordering the north head of Kaipara Harbour. Its short northern boundary 
presents to the waves of the Pacific the bold, rocky promontories, relieved by occasional sand 
beaches, between Cape Maria van Diemen and the North Cape. Its north-eastern limit is 
defined by the sinuous, island-dotted coast from the North Cape to a point some four miles 
west of the Cavalli Islands ; whilst its eastern margin consists of an imaginary line ex- 
tending south for some forty-one miles from the north-east coast-line, thence east for 
12^ miles, and finally south again for fifty-four miles more (see plan facing page x). 

Like almost every other part of New Zealand, the Hokianga Division presents many 
features of interest to the miner, to the geologist, to the geographer, and to the intelligent 
traveller. Its rolling hills were formerly clad with a dense kauri forest, and even yet some 
large patches of this magnificent and valuable timber tree are to be seen. Though worked 
for years, its extensive stretches of clay land still contain considerable deposits of kauri- 
1 — Whangaroa. 



gum, the product of forests long since destroyed. Within its limits is found a variety of mineral 
deposits, some of which may yet prove of economic value. Its wave-swept shores show the 
eflfect of many oscillations in level ; while its surface of rocks of widely varying age and com- 
position exhibits graphically the effects of sculpturing by wind, stream, and sea. 

Economic Reasons for Work in Hokianga Division. 
The known mineral wealth of the Hokianga Division, if we except the widely distributed 
kauri-gum, is not great. It includes the copper-lodes near Whangaroa Harbour, the beds 
containing mercury at the hot springs near Ohaeawai, and small deposits of iron-ore, of which 
the most important are those near the headwaters of the Waitangi River. Quartz veins 
occur at Mount Camel and possibly at other places outside the special area to be described 
in this bulletin, but as yet it has not been ascertained whether or not they carry values in the 
precious metals. Moreover, since the many unfrequented parts of the division have been here- 
tofore but casually examined, it is hoped that a careful survey will not only give a fuller con- 
ception of the ore-bodies already known, but may also aid in the discovery of deposits as 
yet unfound. In investigating the mineral wealth it is of course necessary to consider as 
well the stratigraphy, the physiography, and many other questions of a geological nature. 

Area described in this Bulletin. 

The first work undertaken by the present Geological Survey in the Hokianga Division 
deals with that portion on which this report is based — namely, the Whangaroa Subdivision. 

The Whangaroa Subdivision, lying on the eastern margin of the Hokianga Division, 
comprises the survey districts of Whangaroa, Kaeo, and Omapere, and covers an area of about 
four hundred square miles. The subdivision forms a strip of country 12| miles wide and about 
thirty-four miles long. Its northern and eastern boundaries coincide with those of the Hokianga 
Division. Its western boundary is a line running southwards from Tupo Bay (about half-way 
between WTiangaroa and Mangonui), and its southern boundary is a line running east and 
west about one mile south of Kaikohe Township. 

The subdivision contains deposits of copper-ore near the Pupuke River, mercury-bearing 
hot springs near Ohaeawai, and other features of interest which will be described later. 

Plan of conducting Work. 

All streams and other features which seemed likely to afford outcrops were traversed with 
chain and compass, geological notes being made usually at the same time. The almost con- 
tinuous exposure of solid rock along the sea-front yields much fuller information as to the 
natiire and relationships of the rocks exposed than can be obtained from the creeks and ridges 
of the interior, where the outcrops are usually covered by rock-waste. A careful chained 
traverse was therefore made of every portion of the coast-line and of several small outlying 
islands. Surveys were carried out in greater detail in those areas in which it seemed likely 
that deposits of economic value would occur. In the sounding of lakes the position of stations 
was determined by triangulation. 

The ordinary field-work was mapped on a scale of 20 chains to the inch on large sheets, 
on which all available topographical surveys made by the Lands and Survey Department had 
previously been placed. Specially detailed work in two areas was mapped on a scale of 5 chains 
to the inch. 

Fauna. 

The widespread destruction of the bush has relegated the indigenous fauna to the 
remotest corners of the subdivision, but even in its pristine state the northernmost New 
Zealand bush is comparatively devoid of birds — the only class of vertebrates at all fully 
represented in the Dominion's land-fauna. 



PLATE 11. 




Kalim Ulsii. 

Aijntliis iiKsfrali!^, /)rn'ii///iy//iitii hilifuliiiin . rrpyrinelia htinkx'ii, Aftdia trinrrra, and (.'n/iuin IkiIhuo- 

rurpa in foreground. 
Iliilhlin Xo. S.] [Fare p. 



3 

Tuis (Prosthemadera novce-zelandiw), pigeons (Hemiphaga novce-zdandicB), kiwis of the 
small variety {Apteryx australis), and fantails (Rhipidura flabellifera) are relatively abundant. 
Kakas {Nestor meridionalis) are occasionally heard screaming and whistling in the tree-tops. 
In the spring the valleys resound with the songs of the pipiwharauroa {Chalcococcyx lucidus) and 
riroriro {Gerygone flaviventris). Amongst water-birds, wild-duck {Anas supercUiosa), bittern 
{Botaurus poeciloptilus), pukcko {Porphyrio nielauonohis), blue herons {Ardea sacra), and kuaka 
{Liniosa novce-zelandicc) are the most prominent. The migrations of the last-named bird 
are of great interest, and are described by Buller.* 

Amongst lowlier land-denizens the small brown lizard {Liolepisma moco) is very common, 
especially on Oruatemanu Island. 

Of fresh- water fish, the eel {Anguilla aucklandii) is the chief representative, though small 
kokopus {Galaxias altenuatus) are to be found in almost e\<rv stream. The larger species 
{Galaxias fascialus) is not so common. The fresh-water crayfish {Paranephops planifrons) and 
mussel {Diplodon 7Hemicsi) are of fairly general occurrence, the latter especially in Lake 
Omapere. Amongst land-shells the large pupurangi {Paryphanta busbyi) is the most 
remarkable. 

A considerable number of introduced animals have become naturalised. Wild cattle 
and pigs are common in the lea.st-settled parts. Cats, and probably more than one species of 
the weasel family, arc increasing, and cause great havoc amongst ground-nesting birds, such as 
pheasants. Amongst exotic birds, besides the ubiquitous sparrows, larks, and thrushes, 
Californian quail and Chinese pheasants are fairly abundant. 

The Australian frog (Ilyla aurea) is very common m the swamps. 

Trout have been placed in Lake Omapere, and are said to be now established there. 

FLORA.f 

The present state of the native flora in the Whangaroa Subdivision gives but a poor 
idea of its former wealth and variety. To the wholesale destruction wrought by man has 
been added the partial extinction of the smaller and more delicate plants by cattle and pigs, 
which have roamed through almost every acre of forest in search of food. 

The area under consideration is not of sufficiently varied altitude to give rise to the dis- 
tinct plant-groups which nuirk different levels in a mountainous country. However, certain 
species of plants generally characterize exposed or sheltered localities and soil of poor or 
good quality. 

Considering the flora from this ecological standpoint it may be divided into : — 

(a.) The coastal flora. 

(6.) The flora of the mangrove swamps. 

(c.) The flora of the older lava and clay uplands. 

{d.) The flora of the swamps. 

(e.) The flora of the more fertile land (river-valleys and later lava-flows). 

{/.) The flora of the kauri forest, 
(o.) The coastal type of vegetation is confined to the cliffs and slopes immediately border- 
ing on the sea-coast, and to the valleys debouching thereon. On the open coast the vegeta- 
tion is exposed to frequent easterly gales, which prohibit the growth of any but the hardiest 
plants. The tops of the wind-swept trees and shrubs are bent over to the leeward, and the 
twigs interlaced. The more prominent members of this plant-association are the kahikatoa 
{Leptospermum scoparium), maimka {L. ericoides), Pittosporum crassifolium, Panax lessonii, 
and Metrosideros tomentosa. The pohutukawa {Melrosideros tonienlosa), well known for its 

♦ " History of the Birds of New Zealand," 1888, vol. ii, p. 40. 

f The writers are much indebted to .Mr. T. F. Cheesman, F.L.S., &c., for help in compiling this section. 

1* — Whangaroa. 



magnificent crimson blossoms, grows freely just above high-water mark in all but the most 
exposed situations. The rock-faces are clothed with the New Zealand rock-lily (Arthropodium 
cirrhatum) and Astdia banksii, and in places draped with the creeper Ipomea palmata. This 
last-named plant, which, with its masses of mauve-coloured flowers, forms a most striking 
feature of the coastal scenery during the early months of the year, does not grow in such luxuri- 
ance south of the Whangaroa Subdivision. On the rocks within reach of the salt spraj^, thick- 
leaved plants (of which Salicornia australis and the beautiful pink-flowered Mesembryanthemum 
australe are the most prominent) occupy every possible crack and hollow. The white- 
flowered Clematis indivisa climbs freely over the wind-swept scrub, its handsome masses of 
white flowers making it very noticeable in early spring. The exposed seaward slopes, that 
have been cleared, maintain a fairly thick sward of the hardier grasses, amongst which the 
native Danthonia semiannidaris and D. filosa are predominant, whilst the more sheltered 
of the seaward slopes and the sandy flats at the mouths of the small streams, from which 
the bush and scrub have been cut, support a more luxuriant vegetation. Flax {Phormium 
tenax) of good quality is abundant in the moistcr localities, while the valleys of the many 
small streams which flow directly into the sea are forested with a " mixed bush " composed 
of such forms as whau {Entelea arhorescens), kohekohe {Dysoocylum spectabile), karaka (Cory- 
nocarpus Icevigata), yellow kowhai (Sophora tetraptera), puriri [Vitex lucens), taraire (Beil- 
schmiedia tarairi), and pukapuka (Bmchyglottis re panda). 

(6.) The mangrove swamps form a very characteristic feature of the North Auckland 
peninsula. Their plant-association is a simple yet striking one. The mangrove trees {Avi- 
cennia officinalis), with, their gnarled wide-spreading trunks and branches, bearing the cha- 
racteristic dull-green leathery foliage, rise at regular intervals from the mud-flat, the whole 
surface of which bristles with the small barnacle-covered asparagus-like pneumatophores, 
which project above the mud and supply air to the maia roots. As the outer edge of the 
swamp advances by insilting, and the inner part dries somewhat, the mangroves on the 
landward side, where presumably the swamp has become " mangrove sick," die out, 
and their place is taken by Chenopodium glaucum, Salicornia australis, Juncus maritimus, 
and Cladium junceum, amongst which there grows an abundance of the little white- 
flowered Samolus repens. As the swamp dries still more the sedges are partly replaced 
by Olearia solandri. 

(c.) The Older Lava and Clay Uplands. — There is no doubt that the clay gum-lands, which 
cover a considerable portion of the subdivision, were formerly clothed with a dense grou'th 
of kauri forest, and that the " ironstone " country (composed of lavas of the Kerikeri Series), 
which occupies most of the eastern portion of the subdivision, was covered with " mixed 
bush." Since the removal of this forest the land seems capable of supporting little else than 
a stunted growth of scrub {Leptospermum scoparium), largely replaced on the " ironstone " 
land by bracken {Pteris aquilina), often only a few inches ia height. With the scrub and 
bracken are associated several small shrubs. Particularly abundant among the latter is the 
kumarahou {Pomaderris elliptica), a plant characteristic of the whole North Auckland penin- 
sula. In early spring the yellow-flowered panicles of the kumarahou impart a touch of colour 
to the otherwise sombre landscape. Pomaderris edgerleyi, P. phylicaefolia, Drosera auricvlata, 
Haloragis tetragyna, Lagenophora forsteri (native daisy), the heath-like plants Cyathodes acerosa, 
Leucopogon fasciculatus, L. fraseri, Epacris pauciflora, Dracophjllum urvilleanmn, and the 
orchids Thelymitra longifolia and Microtis porrifolia are also common. 

(d.) The Swamps. — Two types of swamp vegetation may be distinguished — that of the 
swamps on the old lava and clay uplands, and that of the swamps on the more fertile land. 

The first-mentioned swamps are almost solely occupied by the sedges Cladium glomeratum 
and C. teretifolium. In the drier parts, sundews (Drosera binata) and flax (Phormium tenax) 
are usuallv to be found. 



PLATE III. 




J.ookjm; Sou I ii-\\ i>t ikom ()i;oTi;iii;. 

Mixed liiish" ill foreground, undulating Kerikeii Plains against sky-line, descoiuliiii; iii.ru)itly to 

Upokorau Creek. 




ButUtin Xo. S.] 



•'.Mi.\i;u Jksii " ox Si.oi'Ks or Mai:noaemik.mi llii.i,. 
•Shows principally Ueilschmiedia tarairi and R/iopalostijlis sapida. 



[Fare p. I/. 



The swamps on the richer land support a ranker and more varied vegetation. Especially 
characteristic of the wetter portion is the raupo {Typha angustifolia), whilst round the edges 
several species of grass flourish. The swamps of the more fertile areas are in some places 
still occupied by the remnants of great forests of kahikatea {Podocarpus dacrydioides), amongst 
which the kiekie [Freycinetia banksii) grows in great profusion. 

(e.) The alluvial flats and later lava-flows, where not cleared for settlement, are covered 
with a luxuriant growth of " mixed bush." A well-known member of this plant-association 
is the puriri (Vitex lucens) — a tree which, however, where left standing in clumps in the 
clearing of the land is even more noticeable than in the forest. Its handsome foliage, 
delicately coloured flowers and fruit, and sturdy oak-like shape, then make it a feature of the 
landscape. Equally noticeable and abundant in the untouched bush is the graceful nikau 
(Rhopalostylis sapida). Prominent also amongst the larger plants of the " mixed bush " are 
kohekohe (Dysoxylum speclabile), rata {Metrosideros rohusta), piikatea (Laurelia novcE-zelandice), 
taraire (BeUschmiedia tarairi), tawa {B. tawa), totara {Podocarpus totara), rimu {Dacrydinm 
cupressinum), and several species of tree-ferns. The ground and the tree-trunks are covered 
with a dense growth of smaller flowering-plants, ferns, and mosses. (Plate III.) 

Amongst smaller flowering-plants, especially noticeable in the drier parts of the bush, are 
— bush-lawyer (Riibus australis), supplejack {Rhipoijonuni scandens), puwhai-awhara {Astelia 
solandri), and the grass Microlcena avcnacea. In the damp sheltered gullies, where there is 
a ranker growth, perhaps the most conspicuous of flowering-plants are — tutu (Coriaria rusci- 
folia). Fuchsia excorticata, Alscuosmia macrophylla, and haugeliange {(jeniostoma ligustrifolium). 
The parataniwlia {Elatostemma rugosiuii) is also abundant, covering steep damp faces. An 
interesting plant, occurring in profusion in some of the sheltered gullies, is the oru (Colensoa 
physaloides), which attains its southernmost limit in the Whangaroa Subdivision. Especially 
characteristic of clearings in the bush is the makomako, or wine-berry (Aristotelia raceynosa), and 
equally representative of the open alluvial flats is the cabbage-tree, or ti (Cordyline australis). 

(/.) The Kauri Forest. — Kauri forest formerly covered all that part of the subdivision 
underlain by sedimentary rocks, and many parts of the lava plateau, amounting in all to an 
area of considerably more than two hundred square miles. It is now limited — with the excep- 
tion of some isolated clumps — to the watershed of the Waipapa River. 

Owing to the absence from its stem and branches of irregularities which would allow 
of the accumulation of humus, the kauri (Agathis australis) is almost devoid of epiphytic 
vegetation, and its huge, bare, rounded boles and branches form a striking contrast to the 
other smaller forest trees, often densely clad with clinging epiphj^tes. 

On account of the great size of its root and branch systems, only a few small rather 
xerophytic plants can grow under the shadow of the kauri. The most characteristic of accom- 
panying plants is the kauri grass (Astelia trinerva), and almost equally abundant is the toe- 
kiwi {Gahnia habenocarpa). Other common plants are : Mahoe {Melycitus macrophyllus), 
Corokia buddleoides, Alseuosmia macro jihylln, kie-kie {Freycinetia banksii), and the neinei 
{DracophyUum latifoliwn) ; whilst on the dry ridges the fragrant mairehau {Phebalium nudum) 
is abundant ; and at the highest altitudes of the subdivision the tawiri (Ixerba brexioides), 
with its large white flowers, is very noticeable. (Plate II.) 

Naturalised Plants. — Amongst the nmltitude of foreign plants which have become natu- 
ralised in the subdivision, the gorse, briar, bramble, hakea, foxglove, willow, and watercress 
call for notice. Gorse, briar, and branil)le are widespread, especially in the older-settled 
parts of the district and on land owned by the Maoris. The Australian plant Hakea avicularis 
is rapidly spreading on the lava tableland just to the east of the subdivision, and will probably 
soon be a serious menace to farmers. The foxglove is very abundant on the stony surface 
of the later lava-flows. Willows grow freely in the valleys of the Waitansji and Kaeo rivers, 
and watercress in the streams in the more settled parts of the area. 



6 

Timber and Flax. 

The Whangaroa Subdivdsion still possesses a considerable quantity of the most valuable 
of New Zealand timber trees, though the bush is now confined to the more inaccessible parts 
of the area. Of these trees, the kauri {Agatkis australis) takes precedence as the finest tree of 
the New Zealand forest. It is considered by many competent judges to be the best of all pine 
woods, combining, as it does to a remarkable degree, lightness, ease in working, and freedom 
from flaws, with strength and durability. In addition to its other excellences, the kauri is 
almost unique amongst New Zealand timber trees in possessing buoyancy in fresh water when 
first felled. It is therefore capable of being immediately floated down the streams, and so 
affords a quick return to the lumberman. For these various reasons the kauri alone was 
removed in the early days, other useful trees being generally burnt or allowed to rot. 

Of timber trees other than the kauri, the totara {Podocarpus Mara), which is especially 
valuable for piles and telegraph-poles and for other uses where durabihty in contact with salt- 
water or earth is required, is not imcommon in the subdivision. The manoao [Dacrydium 
kirkii) is even more durable for use on land, but is comparatively rare. The rimu [Dacrydium 
cupressinum) is fairly abundant, and is a valuable timber for general purposes. The kahikatea 
[Podocarpus dacrydioides) does not now occur in any quantity in the subdivision. Puriri 
( Vitex lucens) is common, and is exceedingly valuable for fencing-posts, railway-sleepers, &c. 
Pohutukawa [Metrosideros tomentosa) is particularly serviceable for k^lees and ribs in ship- 
building, but the supply is now very limited. Rata [Metrosideros robusta) is fairly abundant, 
but is not much used. Maire [Fusanus cunninghamii) and akeake [Dodoncea viscosa) are 
valuable for the making of wheels, mauls, &c., but the supply is small. Taraire [Beilschmiedia 
tarairi), which is now coming into use for purposes where durability is not required, is widely 
distributed in the Whangaroa Subdivision. Pukatea [Laurelia novcB-zealandicB), which is less 
common, is also finding a limited market. 

Flax [Phormium tenax) of fair quality is found in many parts of the subdivision, but 
with the exception of the swamps surroimding Lake Omapere and those near the head of the 
Waikaraka Stream it does not grow in sufficient quantities to warrant milling. 

Soil and Agrioulture. 

A great portion of the subdivision is occupied by the barren uplands of the older lava-flows 
and by equally improductive clav gumfields. The soil of the narrow flood-plains of the 
Pupuke, Kaeo, Tauranga, Waihou, Utakura, Mangataraire*, and Waitangi rivers is of fair 
or good quality, as is also the land covered by the later basaltic lava-flows, and two smaU 
areas underlain by limestones and calcareous sandstones in the Waihou and Mangataraire* 
valleys. 

The land imderlain by the older lava-flows (locally known as " ironstone land," from 
the lumps of red ochre and limonite which strew its surface), although formerly covered by 
mixed bush, seems now almost entirely barren. 

The following soil-analysis of a sample of " ironstone soil " from near the Whau 
Hill by jVIt. B. C. Aston, Chief Chemist of the Department of Agriculture, displays 
graphically the deficiencies of this soil : — 

"Soil 

Residue on washing . . 



Capacity for holding water 
Capillarity . . 
Reaction to htmus 



Fine sandy loam. 

Fair ; polished rock-fragments. 

Fair. 

Excellent. 

Neutral. 



* In Omapere Survey District. 



MECHANICAL ANALYSIS. 



Stones 
Gravel 
Fine'gravel 
Coarse sand 
Fine sand 
Silt 

Fine silt 
Clay 
Moisture, &c 



Per Cent. 

Nil. 

Nil. 

Trace. 

7-0 

60-6\ 

4-4 

6-4 

11-4 

17-2 



1000/ 



PHEMICAL ANALYSIS. 

' Moisture 

Organic matter and combined water . . 
Total nitrogen 
Available — 

Potash (K.O) . . 
Phosphoric acid (P2O5) 
Colour of citric-acid extract on ignition, greyish-brown. 



Per Cent. 
4-34 
17-56 
0-232 

0006 
0003 



" Hydrochloric-acid Extract. 



' LiraeT(CaO) 
Magnesia (MgO) 
Potash 
Phosphoric acid 



Per Genu 
015 
012 
0-08 
0-048.' 



Mr. Aston remarks : — 

" This soil differs mostly from the specimen of ' gum-land soil '* in the much greater 
amount of organic matter present in the former. It is, however, largely in the form of unde- 
composed root-fibres. 

" Liming with a suitable form of lime, and green manuring, should nmch improve this 
soil. The infertility is probably due to deficiency of available plant-food. 

" I have several ideas as to the way in which freeing of phosphoric acid may be accom- 
plished, and will refer them to the proper ([uarter, in order that field experiments may be 
carried out." 

The clay gum- lands are considered by many to be more likely to repay cultivation than 
the ironstone land. The following soil-analysis by Mr. Aston of a sample of " gum-land soil " 
from near the Kaeo-Ohaeawai Road is of interest : — 



Soil 

Residue on washing 
Capacity for holding water 
Capillarity 
Reaction to litmus 



Fine sandy loam. 
Very small. 
Very good. 
Fair. 
Slightly acid. 



' See soil-aaalysiB below. 



s 



MECHANICAL ANALYSIS. 



Stones 






Gravel 






Fine gravel 






Coarse sand 






Fine sand . . 






sut 






Fine silt . . 






Clay 






Moisture, &c. 







Per Cent. 
Nil. 



Trace. 

58-2 

12-6 

12-2 

9-6 

74 



CHEMICAL ANALYSIS. 

Moisture . . 

Organic matter and combined water . . 

Total nitrogen 

Available — 

Potash (K2O) . . 

Phosphoric acid (PaOg) . . 
Colour of citric-acid extract on ignition, greyish-brown. 



Hydrochloric- acid Extract. 



" Lime (CaO) 
Magnesia (MgO) 
Potash 
Phosphoric acid 



1000 



Per Cent. 
1-54 
5-50 
0102 

0004 
0003 



Per Cent. 
008 

004 
006 
0032." 



Mr. Aston says : — 

" The cause of the infertility of this soil is probably deficiency of organic matter, and 
deficiency of available plant-food. 

" The rational treatment is to lime, preferably with carbonate of lime, and grow heavy 
leguminous crops, which should be ploughed in. Manuring ^ith potash and phosphoric acid, 
when the land is got into good tilth, should improve the yields considerably." 

Land of fairly good quality covers an area of about forty square miles in the subdivision. 
That underlain by the later lava-flows is good dairying country, but is in many places too 
stony to be ploughable. The river-flats are suitable for general agriculture, but many of 
them being owned by Maoris are at present unimproved. 

The small area of limestone or calcareous sandstone country in the Waihou and Manga- 
taraire* valleys is of high quality, but too broken to be used for an\"thing but grazing. 

In view of the ease with which Lake Omapere might be drained, the following soil-analysis 
by Mr. Aston of the silt which forms a thick covering over the floor of the lake may be 
of interest. It should be noted, however, that the sample, though a general one, was taken 
from the eastern half of the lake, which receives drainage from a fertile countrj- of the later 
basic volcanics. It is imlikely that the silt from the western half, which drains mainly 
barren doleritic, rhyolitic, and clay land, would give such good results : — 



* In Omapere Survey District. 



PLATE lY 







l.AKK OMAllliF KliOM WksTKHX SlDK. I'uUKU.N ui Ivi.lilKKIW T.Mll.l. I.A.NU IN l''oHI-.i.|iUUi\U. 




bulletin Xo. 8.] 



\iE\\ OK I'ltahi H[i,l across Lake Omai-kke. 



[I'^acc '[). 8. 



9 



■ Soil 
Washed residue 



Capillarity . . 

Capacity for holding water 

Reaction to litmus . . 



Qay. 

Very small residue, consisting chiefly of 

worn siliceous rock-particles, and a few 

shiny black fragments. 
Good. ' 
Very good. 
Acid. 



MECHANICAL ANALYSIS. 



Stones 

Gravel 

Fine gravel 

Coarse sand 

Fine sand . 

Silt 

Fine silt . 

Clay 

Moisture, &c 



Per Cent. 

Nil. 



Trace. 
2346 
18-12 
11-36 
38-42 
8-64 



100-00 



CHEMICAL ANALYSIS. 

" Organic matter 
Moisture . . 
Total nitrogen 
Available — 

Potash (KjO) . . 

Phosphoric acid (PoO.) 
Colour of citric-acid extract on ignition, dark reddish-brown. 



Per Cent. 
10-70 
9-84 
0-256 

0-015 
0010 



Hydrochloric-acid Extract. 



Potash 

Phosphoric acid 

No sulphur detected on heating." 



Per Cent. 
0-15 
008 



Mr. Aston concludes that " there is nothing in the analysis to show that this soil will 
not be fertile when drained and aerated and properly manured. The phosphoric acid is 
present in small quantity, both total and available, and to grow good crops it will no doubt 
be necessary to fertilise heavily with phosphatic manures." 

The drier parts of the mangrove swamps of Whangaroa Harbour might with compara- 
tive ease be utilised for agricultural purposes. The subjoined soil-analysis by Mr. Aston 
shows the quality of the land formed by these swamps : — 

" Soil . . . . . . . . . . . . Fine sandy loam. 



Residue on washing 
Capacity for holding water 
Capillarity 
Reaction to litmus 



Very small. 
Very good. 
Poor. 

Alkaline, 



10 



MECHANICAL ANALYSIS. 



' Stones 
Gravel 
Fine gravel 
Coarse sand 
Fine sand 
Silt 

Fine silt . . 
Clay 
Moisture, &c. 



CHEMICAL ANALYSIS. 

Moisture 

Organic matter and combined water . . 

Total nitrogen 

Available — 

Potash (K 2 0) .. 

Phosphoric acid (PjOg) . . 
Colour of citric-acid extract on ignition, light brown. 



Per Cent. 

Nil. 



Trace. 
54-4 
120 
12-2 
15-6 
5-8 



1000 

Per Cent. 
316 
7-30 
015 

0038 
0035 



Hydrochloric-acid Extract 



Per Cent. 

0-4 

0-6 

0-61 

0-10" 



" Lime (CaO) 
Magnesia (MgO) 
Potash 

Phosphoric acid 
The following remarks are of interest : — 

" I should hardly call this a calcareous soil, with 0-4 per cent, lime in it, but it is better 
supplied with calcic carbonate than most New Zealand soils. 

" The interesting point in the analysis is the large amount of plant-food rendered avail- 
able by the salt water. The land would, if drained, certainly be fertile for certain crops which 
thrive in salt-laden soils, such as CrucifercB and Chenopodiacece. I would refer you to my 
report for 1907, page 19, for some remarks on salty-soil treatment. 

" The application of the mud to adjoining soils would no doubt improve them, though 
whether such application would be economical is questionable, in view of the cost of labour. 
It would, I think, be cheaper to purchase salt, superphosphate, lime, and potash, and apply 
them to the soils which would benefit by the mud."* 

Climate. 
The climate of the North Auckland peninsula, of which the Whangaroa Subdivision 
forms a small part, is warm and temperate, and, being typically insular, is moist, equable, 
and rather enervating. From a series of observations extending over three years, taken at 
the Waimate North Public School, it appears that the two months showing the highest mean 
temperature — about 67° Fahr. (excluding January, when observations are not made) — are 
those of March and December ; and the month showing the lowest — 52° Fahr. — is that of 
July. The average for January is possibly higher than 67° Fahr. 



* This is in response to a question as to the value of the mud as a manure for the neighbouring clay 
gum-land. * 



11 

The prevailing winds are westerly, but during the summer months a dry easterly wind — 
a southerly extension of the south-east trades — frequently blows for five or six weeks. 

The rainfall is moderately heavy, and is evenly distributed throughout the year. 

No observations on rainfall are available for the actual area under consideration. How- 
ever, a fully equipped meteorological station was in existence at Mangonui, to the north of 
the subdivision, from 1864 to 1878. Rainfall statistics from January, 1899, to August, 1908, 
are also available from Mangonui, Rangiahua (just outside the western boundary), and Paka- 
raka (a few miles to the south-east of the subdivision). Taking an average of the monthly 
rainfalls at these three stations from January, 1899. to August, 1908, and at Mangonui between 
the years 1864 and 1878, the following results are obtained, which may be considered to repre- 
sent fairly accurately the conditions within the subdivision : — 



Months tvith Least RainfaU. 



February . 
November 
December 



Months toith Greatest Rainfall. 



Average 


Monthly 
3-89 in. 
3-89 in. 
3-61 in. 


Rainfall 


Average Monthly 
.. 5-41 in. 


Rainfall 




6-50 in. 






6-30 in. 






4-53 in. 





May 

Jxme 

July 

Remaining six months 

The average of the annual rainfalls recorded at Mangonui, Rangiahua, and Pakaraka 
during the periods given above, is 56-78 in. 

Scenery. 

From a scenic standpoint there is much to please the traveller in the Whangaroa Sub- 
division. Popular interest centres round the superb harbour of Whangaroa (Frontispiece 
and Plates VllI to X), with its narrow rock-walled entrance ; with its numerous deep and 
sinuous bays, gay in midsummer with the crimson flower of the pohutukawa, bordered In- 
rugged castellated crags or by more gradual slopes ; with its dark forest, coming in places to 
the water's edge ; and with its scattered and isolated settlements, both P^uropean and Maori. 
The larger streams generally enter the harbour amid mangrove swamps, but in places a brook 
dashes over the volcanic rocks in a waterfall of considerable beauty. Here and there a rock- 
girt island dots its placid surface ; while the cliffs which abut against the water near the 
harbour-entrance are carved into fantastic shapes — colunms, pinnacles, and caverns. But 
Whangaroa Harbour, though the largest and most widely known indentation, is not the only 
scenic charm along the rock-bound coast. Tupo, Taupo (Plate VIII), Tauranga, and Mahine- 
pua bays are all beautiful, with their stretches of yellow sand and the deeply dissected 
hills in the background ; while between them rugged, and in places vertical, cliffs present 
a bold front to the waves of the Southern Pacific. 

In the interior the gently undulating stretches of gum-land and lava plateau, broken 
by ranges of densely forested hills (Plates III, V, &c.), exhibit an expansive but distinctly 
monotonous landscape. The blue waters of Lake Omapere, with the symmetrical cone of Te 
Ahuahu in the background (Plate IV), give a pleasing effect, but the absence of colour 
detracts from the ensemble. The slopes of Maungaemiemi and other heights show many 
woodland streams bordered by nikau palms and tree-ferns, with here and there a majestic 
kauri rising above the lower forest. 



12 

So early as 1835 Darwin* described the quiet beauty of Wairaate North in contradis- 
tinction to the widespread savagery around it. Even to-day the cultivated farm-lands''give a 
pastoral charm to the decayed settlement. The fertile valley of the Kaeo, with its farms 
and habitations, and its willow- bordered meandering river, contrasts pleasingly with the 
barren hills on either side. 

Literature. 
The following list includes, so far as the writers are aware, all publications which con- 
tain anything of interest on the geology or topography of the Whangaroa Subdivision. 
The following abbreviations are used : — 

Rep. G.S. : Reports of the Geological Survey of New Zealand. 
Trans. : Transactions and Proceedings of the New Zealand Institute. 
A capital letter followed by a figure (thus, C.-3) refers to a New Zealand parliamentary 
paper. 

1839. Polack, J. S. : " New Zealand, being a Narrative of Travels and Adventures in that 
Country between the Years 1831 and 1837." Vol. i, pp. 247-9, description of Wha- 
ngaroa Harbour. 

1839. " Narrative of the Surveying Voyages of HisTMajesty's Ships ' Adventure ' and 
' Beagle.' " Vol. ii, p. 601, and vol. iii, p. 502, account of a visit to Waimate North. 

1843. Dieffenbach, E. : " Travels in New Zealand." Vol. i, p. 239, &c., brief description 
of scenery and geology of Whangaroa Harbour and of the southern part of the 
subdivision. 

1866. Hector, J. : " Geological Sketch-map of Northern District of Auckland." 

1866. Hector, J. : Rep. G.S., No. 1. " On the Coal Deposits of New Zealand." P. 44, descrip- 
tion and analysis of " Brown Coal from Kaiou River, Whangaroa Harbour." 

1870. Hutton, F. W. : " On the Occurrence of Native Mercury near Pakaraka, Bay of Islands." 
Trans., vol vi, p. 252. Describes the Ohaeawai Hot Springs, and the finding of 
native mercury and other minerals there. Gives partial analysis of water. 

1872. Hector, J. : Rep. G.S., No. 7, p. 153. " Report on the Coal-seams at Wangaroa and 
Mangonui." Reports a coal-seam 2 ft. thick near the head of Whangaroa Harbour, 
which, however, is not persistent ; also mentions alleged discovery of a thick seam of 
coal in the upper part of the Kaeo Valley. 

1877. Hector, J. : Rep. G.S., No. 9. " Progress Report," p. iv. Summarises McKay's report ; 
briefly refers to Ohaeawai Hot Springs, and says that the Kaeo Valley greensands 
are equivalent to the beds overlying the coal at Kawakawa, and are separated from 
the Inoceramus beds of the Amuri Series by beds of quartzose grit. 

1877. McKay, A. : Rep. G.S., No. 9, p. 55. " Report on Wangaroa North." Discusses 
the geology of the northern part of the subdivision. 

1877. Skey, W. : " On Certain of the Mineral Waters of New Zealand." Trans., vol. x, p. 425. 
Gives analysis of water from Ohaeawai Hot Springs, also of the deposit formed by 
these springs. 

1880. Smith, S. Percy : " On Some Indications of Changes in the Level of the Coast-line 

in the Northern Part of the North Island." Trans, vol. xiii, p. 398. Considers that 
at Whangaroa there is evidence of recent elevation. 

1881. Cox, S. H. : "Notes on the Mineralogy of New Zealand." Trans., vol. xiv, p. 418. 

Contains a few references to minerals occurring in the Whangaroa Subdivision. 

1882. Cox, S. H. : "Notes on the Mineralogy of New Zealand." Trans., vol. xv, p. 361. 

Contains a few references to minerals occurring in the Whangaroa Subdivision. 

* " Journal of Researches during the Voyage of H.M.S. ' Beagle,' " 1890 (new edition), pp. 444—58. 



13 

1884. McKay, A. : Rep. G.S., No. Hi, p. 110. " Ou the Geology of the Coal-bearing Area 
between Whangarei and Hokianga." Deals with the succession of the Cretaceo- 
Tertiary rocks which lie partly in the southern portion of the subdivision. 

1888. Becker, G. F. : " Geology of the Quicksilver Deposits of the Pacific Slope." 
U.S. Geol. Surv., monograph xiii, pp. 49-50. Describes briefly the Ohaeawai 
Hot Springs. 

1888. Hector, J. : Rep. G.S., No. 19. " Progress Report," p. xxxv. Summary of McKay's 
report. 

1888. McKay, A. : Rep. G.S., No. 19, p. 37. " On the Geology of the Northern District of 

Auckland." Describes the geology of the southern part of the subdivision, 
and discusses the bearing of his paliBontological discoveries on the Cretaceo-Tertiary 
problem. 

1889. Hutton, F. W. : " On the Relative Ages of the New Zealand Coalfields." Trans., 

vol. xxii., p. 377. An important paper in which the Cretaceo-Tertiary question is 
fully discussed, and w hich thus bears on the relations of the different members of 
the Kaco Series of this bulletin. 

1890. Darwin, (Tiarles : " Journal of Researches into the Natural History and Geology of the 

Countries visited during the Voyage round the World of H.M.S. 'Beagle.'" (New 
edition.) Pp. 444-58, account of visit to Waimate North, &c. 

1892. Hector, J. : Rep. G.S., No. 21. " Progress Report," p. xxx, nature, origin, and amount 
of Okaihau iron-ore ; p. Ixxxi, &c., summarises McKay's report, and describes a 
mineral belt running through Stephenson Island. 

1892. McKay, A. : Rep. G.S., No. 21, p. 65. " Geology of District surrounding Whangaroa 
Harbour." An important paper ou the geology of the northern part of the sub- 
division. 

1892. McKay, A. : Rep. G.S., No. 21, p. 72. " The Lignites of Cooper's Beach, Mangonui." 
Mentions obtaining samples of oil-shales of poor quality in the northern branch of 
the Kaeo River. 

1892. Hector, .1. : Rep. G.S., No. 21, p. 159. " Appendix to Fossiliferous Localities in New 
Zealand." A summary of the geology of the northern part of the subdivision. 

1892. C.-5, p. 13. Reference to discovery of very rich copper-ore north of Auckland — pro- 

bably in the Pupuke Copper-field. 

1893. C.-2, p. 17. References to copper of North Auckland and to cinriahar of Ohaeawai. 

1893. C.-3, p. 187. Brief account of Ohaeawai Hot Springs, and of prospecting for mercury 

by " a syndicate of gentlemen from New South Wales." (The discovery of " a lode 
of cinnabar " referred to was, however, made on Colonel Patterson's property, and 
not on that held by the syndicate.) 

1894. Hector, J. : Rep. G.S., No. 22. " Progress Report," p. Ixxxi. Summary of McKay's 

report. 
1894. McKay, A. : Rep. G.S., No. 22, p. 70. "On the Geology of Hokianga and Mongonui 
Counties." Discusses the geology of the northern portion of the subdivision. 

1894. C.-2, p. 15. Mentions that prospecting for mercury is going on at the Ohaeawai Hot 

Springs. 

1895. C.-2, p. 17. Reference to prospecting carried on by the Colonial Exploration Com- 

pany at Ohaeawai Hot Springs. 

1896. Maxwell, C. F. : " On Alterations in the Coast-line of the North Island of New Zealand." 

Trans., vol. xxix, p. 564. Evidence that throughout the North Auckland peninsula 
the west coast is sinking and the east rising. 
1896. C.-2, p. 12. Reference to continuance of prospecting by the Colonial Exploration 
Company at Ohaeawai Hot Springs. 



14 

1897. C.-2, p. 9. Reference to cessation of work at Ohaeawai Hot Springs. 

1898. CrifKths, A. P. : " The Ohaeawai Quicksilver Deposits." " Transactions New 

Zealand Institute of Mining Engineers, Second Series," vol. ii, p. 48. A 
detailed description of the mercury-deposits, and of the methods adopted in 
working them. 
1898. McKay, A. : C.-9, p. 4. " Report on the Copper Deposits of Omaunu, No. 2, Whangaroa 
County." Describes the geology of the neighbourhood. Advises more systematic 
search for the actual lode. 

1898. C.-3, p. 143. Summarises McKay's report. 

1899. C.-3, p. 33. Further reference to cessation of prospecting at Ohaeawai Hot Springs. 

P. 160, reference to desultory prospecting in Pupuke Copper-field. 

1900. McKay, A. : " Further Notes on the Iron-ores of New Zealand." New Zealand Mines 

Record, 16th July, p. 472. Okaihau iron-ore " certainly exceeds one and may be 
several square miles in extent." {Cf. Ch. VI, p. 94.) Similar lesser deposits also 
exist in the same district. 

1903. Park, J. : " On the Age and Relations of the New Zealand Coalfields." Trans., 

vol. xxxvi, p. 405. Discusses the relations of the different members of 
the coal-bearing rocks of New Zealand, which include the Kaeo Series of this 
bulletin. 

1904. Tregear, E. : " The Maori Race," p. 485. Reference to the megalithic remains re- 

ported from the neighbourhood of Kerikeri. 

1905. New Zealand Mines Record, January, p. 231. Notice of intention of Natives to sell 

land said to contain payable gold in upper reaches of Waihou — possibly Ogle's 
claim. 

1905. Marshall, P. : " The Geography of New Zealand." Contains passing references to 

the subdivision. 

1906. McKay, A. : " The Copper Deposits of New Zealand." " New Zealand Mining Hand- 

book," p. 499. Reference to Pupuke Copper-field. 

1906. C.-2, p. 7. Reference to taking up of leases in the Pupuke Copper-field. 

1906. Gordon, H. A. : " Mining and Engineering and Miners' Guide " (3rd edition). Govern- 
ment Printer, Wellington, p. 12, &c. Passing reference to the occurrence of various 
ores in the subdivision. 

1906. McKay, A. : " Further Notes on the Iron-ores of New Zealand." " New Zealand 

Mining Handbook," p. 472. A reprint from New Zealand Mines Record of July, 
1900. 

1907. Brown, J. M. : " Maori and Polynesian." (Hutchison and Co.) Pp. 5 and 130. 

References to the megalithic remains reported from the neighbourhood of 
Kerikeri. 

1907. Marshall, P. : " Geology of Centre and North of North Island." Trans., vol. xl., p. 79. 
Petrological notes on igneous rocks from the subdivision. 

1907. Marshall, P. : " Distribution of the Igneous Rocks of New Zealand." Report of Aus- 
tralasian Association for the Advancement of Science, p. 366. Brief references to 
the igneous rocks of the subdivision. 

1907. C.-3, p. 7. Reference to prospecting in the Pupuke Copper-field. 

1908. C.-9. Second Annual Report (New Series) of the New Zealand Geological Survey 

Department, pp. 22-24. Contains a short tentative account of the geology of the 
subdivision. 
1908. Bell, J. M. : " New Zealand as a Mining Country.'' Australian Mining Standard, 
vol. xl. No. 1046 (25th November). Mentions the occurrence of iron-ore and copper 
in the subdivision. 



15 

Population and Early History. 

The present population of the Whangaroa Subdivi.sion is about two thousand five hundred, 
of which number about fifteen hundred are Europeans and one thousand Maoris.* The chief 
townships are Kaikohe, with a population of 127 ; Waimate North, of 109 ; Okaihau, of 161 ; 
Kaeo, of 315 ; and Saies and Totara North together, of 205. 

J.-Macmillan Brownf refers to the existence " at Kerikeri in the Bay of Islands " of " a 
miniature Stonehenge with huge blocks standing 6 ft. or 7 ft. above the ground." TregearJ 
also refers to these stones, but only as " looking like Druidical remains," and says that they 
were " anciently used in sun-worship " by the Maoris. Similar remains are said by Brown 
to occur at Atiamuri (about thirty miles north of Lake Taupo). 

During the geological survey of the eastern portion of the Whangaroa Subdivision, careful 
search was made for these monoliths. As the result of inquiries it seeihcd most probable 
that the great heaps of volcanic boulders between Pungaerc and the Whau Hill on the Kohatu 
Whakangaongao Stream were the " remains " in question. There is little doubt, however, 
that these boulders have been derived by differential weathering from the lava-flows which 
cover this part of the country. Similar collections of huge boulders are connnou throughout 
the eastern portion of the subdivision. 

The subdivision was one of the first parts of New Zealand to be settled by Europeans, 
and is full of interesting historical associations. 

At the time of the arrival of the first colonists the country was occupied by the large 
and warlike tribe of the Ngapuhi, which has now, through the ravages of war and disease, 
shrunk to a mere vestige of its former size. 

Whangaroa Harbour was much resorted to in the early days by ships in quest of spars 
— easily obtained from the kauri forests, which then grew almost to the water's edge. In 
1809 occurred the massacre of the crew of the " Boyd." Particulars of this tragedy are to 
be found in most works dealing with the history of New Zealand. The hull of the ill-fated 
vessel was, until quite lately, distinguishable beneath the waters of the harbour. 

The first systematic colonisation was carried on by missionaries belonging to the English, 
Roman Catholic, and Wesleyan Churches, but contemporaneously with their settlement a 
number of independent colonists from New South Wales and elsewhere took up their abode 
in the subdivi.sion. A Wesleyan mission was established near Whangaroa Harbour in 1823, 
but after a few years the missionaries were obliged to leave the district owing to the hostility 
of the Natives. 

Waimate North became in 1830 the headquarters of the Church of England mission, 
initiated by the Rev. Samuel Marsden at the Bay of Islands in 1814. A Roman Catholic 
mis.sion — still in existence — was established near Whangaroa Harbour in 1840. 

In 1845 Hone Heke attempted to overthrow the recently established British suzerainty 
over New Zealand. Two battlefields of the consequent " War in the North " lie within the 
subdivision. On the shores of Lake Omapere, where Heke repulsed the attacks of the British 
soldiers and of the friendly Natives, the rifle-pits and stockade of the pa§ are still to 
be seen. In a hastily constructed fortification at Ohaeawai, near the present village of 
Ngawha, Heke again defied all attempts to dislodge him, though he ultimately abandoned 
the position. 

Industrie?. 
Bushfelling and kauri-gum digging are the only industries at present being carried on 
in the Whangaroa Subdivision which can lay claim to nmch importance. P'lax-milling, 



* The estimate of the Maori population is only approximate. f '" Maori and Polynesian," pp. 5 

and 130. J " The Maori Race," p. 485. § Fortified village or military post. 



16 

dairying, wool-growing, stock-raising, shipbuilding, and fishing may be mentioned as minor 
industries. 

As noted already, the subdivision is endowed with nearly all the more valuable New 
Zealand timber trees. There are at present about 90,000,000 superficial feet of kauri and 
4,000,000 ft. of other valuable timber standing in the subdivision, of which about 25,000,000 ft. 
will probably be " driven " into Whangaroa Harbour. Up to the present only two methods 
have been followed in transporting the trees from the bush to the mills. The more economical 
consists in placing the timber (first, except in the case of the kauri, allowed to dry partially) 
in the bed of a stream, down which it is " driven " during floods, the flood-waters being usually 
augmented by the sudden release (" tripping ") of one or more dams erected up stream. Most 
of the streams in the subdivision are good "driving creeks " — i.e., have a gentle grade through- 
out — although mucl^ expense is caused by the detention of the logs in the lower meandering 
parts. In one case a permanent alteration in drainage was caused by the diversion by means 
of a short canal of the upper waters of the Parirengarenga Creek (the lower part of which is 
unsuitable for " driving " owing to waterfalls) into the'|JRotomanoao Creek. The more 
expensive method of carting or tramming the logs to the sea or to some suitable river has 
to be followed when no " driving creek " is available. In this laborious process bullock- 
teams, and, to a small extent only, traction-engines, have been employed up to the present, 
but in the near future the Kauri Timber Company, of Auckland, proposes to con- 
struct a railway-line, ten miles or more in length, from its large forest (containing about 
30,000,000 ft. of timber) at Puketi to the Bay of Islands. By this means the -bimber 
(mostly sawn into baulks at a mill on the spot) will be much more cheaply and expeditiously 
got to the sea. 

As remarked in the previous section, ships visited Whangaroa Harbour for spars at the 
beginning of the last century. From that time 'till the present the timber trade has been 
the chief industry of the subdivision. Spars and shingles were the main exports till about 
1860, and both before and after that date most of the timber was exported in the form of logs 
squared by hand in the bush. 

The timber trade was at its best between 1875 and 1880. Latterly it has declined, owing 
to lack of material. 

Two timber-mills are at present working in the subdivision. At Totara North, Lane 
and Sons' mill, which has been in existence since 1867, has an output of about 2,000,000 super- 
ficial feet per annum. . At Okaihau a smaller mill worked by water-power and hand-labour 
is said to be capable of turning out about 1,100 ft. per day. 

The kauri-gum industry still supports a large though somewhat nomadic population. 
By far the greater quantity of the gum is dug from the almost treeless " gumfields," once 
the site of great forests which were apparently destroyed by the Maoris before the arrival 
of the white man. Gum is also obtained in the existing kauri forest, both by digging and 
also by bleeding the trees. Bleeding is, however, injurious to the trees, and is seldom 
permitted. 

On the gumfields gum occurs both on the drier uplands and in the swamps. On the diy 
ground the gum is seldom more than a few inches below the surface. These " shallow dig- 
gings " are now almost exhausted. In the swamps gum is found at all levels down to 10 ft. or 
even more. 

In locating gum the earth is probed with a spear (a slender, pointed, steel rod attached 
to a handle). The experienced digger can readily distinguish by the character of the impact 
a piece of gum from a stone or piece of wood. The located gum is then secured by digging, 
or, in swamps, less laboriously by " hooking," a process in which a hooked steel rod is employed. 
Many diggers — notably the Austrians, who are among the most numerous on the fields — 
do not use a spear, but dig the ground over completely, and in the case of swamps take it 






K 




H 




>. 










w 




^ 




u 


< 


o 










p 


J 


« 


o 


<! 


tc 


El 


,^ 


L:) 






-^ 










~ 


S 


r- 


^i! 


5 




wl 


> 




o 






tc 


<D 



3 H 




l'"l.OOD-I'r,AIN OK W.MTAXGI IJlVKK. KkIUKEISI 1'LAINS AGAINST HkY-T.INE. 
Ihlllitin Xo. S.] [/■'firr p. 10. 



17 

out in a face 10 ft. or more in depth, if necessary, draining the swamp as the work 
proceeds. 

The flax trade has latterly been depressed by the fall in the price of fibre. There are 
not, at the date of writinj;,* any flax-mills working in the subdivision, but one was in opera- 
tion at the beginning of 1908, near the headwaters of the Waikaraka Creek. 

The land bordering on the sea-coast is healthy sheep-country, and the sowing of Danlhonia 
after burning off the scrub has considerably increased the production of wool in the subdi- 
vision. Sheep-breeding is also carried on in the interior, in conjunction with dairying and 
the fattening of cattle. 

The rich volcanic land in the south-eastern portion of the subdivision is well suited for 
dairying. A co-operative butter-factory, which has been working for six years at Ohaeawai, 
with an auxiliary creamery at Okaihau, produces about 35 tons of butter annually. 

From Lane and .Sons' shipbuilding yards at Totara North, eighty-four vessels — the 
largest of 320 tons burden — have been launched. Owing to the small demand for wooden 
vessels at the present day the industry is hardly so flourishing as formerly. 

WTiaies — chiefly the blackfish (Glohiocepkalus melas) — are fre(juently seen off the coast, 
but no whaling is now being carried on. About tlie middle of the last century the Bav of 
Islands (to the east of the subdivision) was an important whaling centre, and a whaling- 
station was in existence in about the year 1870 on the small island of Motuekaiti. There 
was a revival of the industry about fifteen years ago, when whaling-stations were established 
on Motuekaibi and at Seasick Bay, on Whangaroa Harbour. 

Several good fishing-grounds exist off the coa.st of the Whangaroa Sul)division, the mo.st 
important fish being the hapuka (Polyprion prognafhus), schnapper (Pagrosomus auratus), 
flounder (Hhnmhoaolen }deheia). kahawai (Arripis tralla). and mullet (Mugil cephnlolus). The 
catching of the crayfish (Ja.tus hugeUi), which abound on the rocky bottom near Whangaroa 
Heads, is at present the chief occupation of the fishers. 



MkANS ok ('o.\I.MrNI(ATI()\. 

Owing to the mild relief of the area under consideration, and the small size of the streams, 
few engineering difficulties have to be contended with in the construction of roads. There 
is, moreover, plenty of good stone for metalling in almost every part of the subdivision, l)ut 
this has so far been used in onlv a few places. The state of tin- roads therefore depends almost 
entirely upon the weather, many becoming nearly impas.sablc in winter. Coach-roads connect 
the settlements of Ohaeawai (just outside the subdivision), Kaikohe, Waimate, Kaeo, Whanga- 
roa, Totara North. Okaihau. I'takura. and Waihou. No attempt can be made to enumerate 
the many side roads and rough tracks which lead in all directions to outlying gum-stores and 
small settlements, and which during the winter months are often practicable only for pack- 
horses. 

Communication l)y mail is, considering the poor roads, wonderfully well maintained. 
All the larger settlements receive two mails a week from .Auckland. 

Telephonic communication is general. There are po.st and telephone offices at Totara 
North, Saies, Whangaroa. Kaeo, Waimate North, Okaihau, Kaikohe, Ngawha, and Te Ahuahu ; 
and a post-office at Utakura. 

History of Mining. 
Though somewhat desultory attempts have been made from time to time to com- 
mence mining operations in the Whaagaroa Subdivision, no successful enterprise, with the 

* November, 1908. 
jj — Whangaroa. 



18 

exception of the widespread tiud still reumuerativ e digj^iug for kauri-gum, has as yet been 
established. 

Mining operations have been carried out on a small scale in two areas in the subdivision — 
at the Pupuke Copper-field, and at the hot springs near Ohaeawai. 

The first discovery of copper-bearing rocks on the Pupuke Copper-field was made by the 
late Mr. Robert Bell, in 1892, on Native land near the present Whangaroa Amalgamated 
Company's No. 4 drive. An inspection was made by the Government Geologist, Mr. A. 
McKay,* who reported favourably, and, as a result, negotiations were commenced by the 
Government for the purchase of a portion of the land from the Natives. The first mining- 
claim was that taken up near the original discovery by Mr. Bell and his friends. Soon after 
Messrs. Hare and I^atjen began prospecting operations on land still held by the Natives. 
Difficulty followed in regard to securing the title to the land from the Maoris, but finallv a 
lease was obtained — not, howeyer, without some litigation with a company known as the 
Ferguson's Mining and Smelting Company (Limited), which also claimed the property, and 
had carried out considerable development on its own account. After these initial troubles 
were over, Messrs. Hare and Ratjen some three years ago formed a registered company 
known as the Hare-Ratjen Company, which has since that date done a considerable 
amount of prospecting, but has not been working for the last year or more. 

Meanwhile the claim originally held by Bell and party was passing through a number 
of hands. Bell's rights having lapsed through non-fulfilment of the conditions of the Mining 
Act, the property was successively restaked by two claimants, who, after some litigation, 
finally allied to form the Whangaroa Amalgamated Company. This company has since carried 
on a good deal of prospecting-work. 

The Ferguson Company, after its failure to hold the Hare-Ratjen ground, took up 
land to the east of the original discovery, and has since then been carrying on explorations 
in different parts of its property. 

Some two miles to the west of the Whangaroa Amalgamated Claim, prospecting for copper 
was prosecuted on the banks of Te Patoa Creek by a company known as the Northern Minerals 
Company. A small inclined shaft was sunk, from which ore is said to have been obtained 
before work was stopped by the influx of water. 

The existence of mercury at the Ohaeawai Hot Springs was known as early as 1866.")" In 
1870 Captain Hutton, in a hurried visit to the locality, succeeded in finding mercury on the 
shores of Tuwhakino Pond, and also apparently in No. 3 area (see detailed map), where it 
occurred, associated with metacinnabarite, in two small veins in the sandstones. 

About 1873 more extensive prospecting was carried on by Mr. G. F. Dickeson. Before 
long the property was leased by the Maoris to Mr. F. Earl, and a small amount of mercury is 
said to have been retorted by this gentleman. On the expiry of the lease, the propertv ulti- 
mately passed into the hands of Colonel G. W. S. Patterson, of Auckland. This gentleman 
instituted further prospecting ; ores of mercury were found in several places, and in 1895 a 
mining company knowm as the Colonial Exploration Company was formed in England through 
his efforts. The mercury-bearing country, which formed one of the 2)roperties uJider the 
company's control, was exploited under tlio direction of Mr. Andre P. Griffiths. A considei- 
able amount of money was expended in sinking prospecting-shafts, and in open cuttings, 
and also in the erection of a reduction plant. The men engaged in the mining operations 
were much inconvenienced by the hot-spring water and sulphurous and other gases, and 
considerable losses of mercury took place at the reduction-works, probably owing to incom- 
plete sublimation in the condensers. Owing to the precautious taken, however, there appear 
to have been no cases of salivation amongst those engaged at the works. 



* ParL Papers, 1898, C.-9, p. 4, f Hutton, Trans., 1870, p. 215. 



19 

In 1897 operations at the Ohaeawai Hot Springs were suspended, according to the 
Mines Statement of that year, owing to litigation between the owners.* 

Some years ago traces of gold were found in the siliceous sedimentaries near the junction 
of the Waihou and Waipapa rivers ; excavating-work was prosecuted until the yield of 
gold from assay-samples was found to be unsatisfactory. f Much the same fate apparently 
attended the e.xploitation of a (|uartz reef in the hills near Kaeo, on the left bank of the 
river.J 

Prospecting for coal near Saies was carried on about the year 1875,§ bore-holes being 
put down and a shaft sunk. Mr. McKay, however, pointed out the uselessness of further 
work in that neighbourhood, and no further efforts to discover coal there have been 
made. 



•Pari. Paiier, C.-2, 1897, p. it. For further details, see Chapter VI, p. 87 et seq. 
f Samples from this locality, collected by the writers, yielded neither gold nor silver. 
t Sec Chapter VI, )> <»3. 
S McKay, Rep. (i.S., No. !», 1874-6 (pub. 1877), p. 55. 



2* -Whangaioa. 



20 
CHAPTER 11. 



OUTLINE OF GEOLOGY. 



I'age fuge 

Sequence of Formations . . . . 20 ! (leneral Account of the Stnicture of the 

Geological History . . . . . . 21 ! Several Formations . . . . 22 

Sequence of Formations. 
The oldest rocks foiuid in the Whangaroa Subdivision consist of a series of argillites, cherts, 
(juartzites, grauwackes, and contemporaneous igneous rocks. As this series has its most 
extensive exposure in the watershed of the Waipapa River, the writers tentativelv propose 
for it the new name of Waipapa, as having no previous associations. It appears in two separate 
areas — namely, along the sea-front, and towards the centre of the subdivision. So far the 
Waipapa rocks have yielded no pal8eontologicale\'idence as to age. but it is supposed, on pureh- 
lithological grounds, that they are either Late Palaeozoic or Early or Middle Mesozoic. 

Unconformably overlying the Waipapa rocks is an extensive series of conglomerates, 
tuffs, concretionary shales, claystones, fossiliferous greensand-s, calcareous sandstones, and 
impure limestones, which will be referred to as the Kaeo Series. The rocks of this series cover 
most of the north-central and southern portions of the subdivision. The fossils of the Kaeo 
rocks appear to indicate an age ranging from Late Mesozoic to Early Tertiary. 

Cutting the Waipapa rocks are a number of dykes of basic and semi-basic composition. 
These are possibly contemporaneous mth larger intrusions of basic and semi-basic rocks 
found intruding the Kaeo rocks. These intrusives are themselves intruded by later dykes 
of a semi-basic character, probably contemporaneous with which are the remnants of a much 
decomposed series of semi-basic pyroclastics. 

The Kaeo Series is unconformably succeeded in the northern part of the subdivision 
by a considerable thickness of semi-basic breccias, with which are associated tuffs and lava- 
flows of the same petrological composition, and minor beds of greenish sandstones. The series- 
has been called Wairakau by the writers, since it has a typical development in the basin of 
the stream of that name. The whole series is, in a few places, penetrated by dykes agreeing 
in chemical composition with the more widespread breccias. Rocks closely resembling those 
of the Wairakau Series are found at intervals from the North Cape to the Coromandel Penin- 
sula, and are generally conceded to be of Miocene age. 

In probable unconformity to the Wairakau rocks is a widespread group consisting of 
doleritic flows, with occasional beds of stratified sediments, which cover a great part of the 
eastern half of the subdivision. The extensive Kerikeri Plains are almost exclusively com- 
posed of the rocks of this series, for which therefore the name Kerikeri seems suitable. 

In various places in the subdivision where Wairakau and Kerikeri rocks outcrop, dykes 
are found penetrating the underlying sedimentaries, and are obviously connected with one 
or other of the overlying igneous rocks. 

In the southern portion of the subdivision, in the neighbourhood of Lake Omapere, are 
found a few puys — one well preserved, the others much dissected — with associated acid 
and basic effusive rocks of rather limited extent. It seems quite probable that no great break 
in time separates these rocks from the rocks of the Kerikeri Series, with which, indeed, they 
may possibly be almost contemporaneous. The basic rocks associated with the well- 
preserved puy of Te Ahuahu, however, are, as proved by field relationship, undoubtedly more 
recent than those of the Kerikeri Series, and are considered to be approximately coeval with 
those of the volcanic cones of the Auckland Isthmus. Scattered fragments of obsidian foimd 
near Pungaere are provisionally assigiied to the same age as the acidic rocks near Lake Omapere. 



•21 

Either during the period intervening between the extrusion of the older and younger 
flows of the later basic rocks, or more probably during the interval which elapsed between 
the Kerikeri eruptions and the later basic eruptions, lacustrine sands, clays, and gravels were 
deposited in the old Ngawha Lake, formed by the daniming-up of the headwaters of a stream 
by the older flows. The old basin lies at the south-east comer of the subdivision. 

High-level terraces in various parts of the subdivision are deposits of probably some- 
what later age than the Ngawha beds. 

Recent beds in the form of sands, gravels, and muds, with local deposits of iron-ore, are 
distributed throughout the subdivision. Muds in tidal swamps and wind-blown and marine 
sands of very minor importance are found in the coastal region. 

The following is a tabular statement of the geological sequence in the subdivision, as 
understood respectively by McKay and by the writers of this report : — 



McKay's Cl.\ssificatios. (Rep. G.S., 1392 and 
1894.) 



Name and Subdivisions of Series. 



Age. 



CliASSIFICATION OF THIS BULLETIN. 



Name and SiibdiTisions of Series. 



Age. 



Te Anau, Maitai, and M'airoa.— 
Mainly Wairoa 



Cretaceo ■ Tertiary. — Sandstones 
and shales, with traces of coal ; 
hydraulic limestone and fire- 
stones 



Kaeo green and brown sandstones 



Devonian to Tri- Waipapa. — Argillites, grauwackes,] Pre-Cretaceous. 
astiic, mainly quartzites, &c., and coutem- 
Triassic. , puraneous igneous rocks 



Cretaceous to Eo- 
cene. 



Tertiary. 



Kaeo. — 

Conglomerate?, tuffs 

Concretionary shales, clay- 
stones, sandstones, and im- 
pure limestones 

Massive limestones 

Qreensands, claystones, and 
calcareous sandstones 



Late Mesozoiu 
and Pearly Ter- 
tiary. 



Manukau or Trachyte ■ Breccia i Pliocene. 
Formation 



Wairakau. — Bieccias, dykes, and 
flows 



Miocene. 



Kerikeri. — Flows and underlying Miocene or post- 
sediments Miocene. 



Acid and basic volcanics (?) 



Swamps 
flats 



and low-lying alluvial 



Ngawha Lake Beds . . 

Acid volcanics and older portion 

of later basic volcanics 
High-level terraces .. 
Later basic volcanics 



Recent. 



Spring, fluviatile, lacustrine, 
and flovio-marine deposits 



Jntrusives and other Igneom 
Rocks of Doubtful Age. — 
Basic and semi-basic intrusives 



Semi-basic pyroclastics, flows, 
and dykes 

Semi-basic dykes and flows . . 



Post-Miocene. 



Recent 



Post- Waipapa and 
probably post- 
Kaeo. 

Younger than the 
igneous rocks 
just mentioned. 

Waiiakau or Keri- 
keri. 



Geological History. 

Any attempt to depict the geological history of a small area like that under discussion 
must be largely speculative, and, when a larger area of the North Auckland Peninsula has 
been examined in detail, the conclusions arrived at will probably require much modification. 

It seems probable that in Palaeozoic times there existed to the north and east of the 
Whangaroa Subdivision a considerable area of ancient rocks. The waste derived from these 



22 

rocks was deposited over at least the whole of the northern portion of the subdivision. Those 
deposits which accumulated near the ancient shore-line are represented at the present day by the 
coarser and more varied shallow-water rocks of the coastal belt of the Waipapa Series, whereas 
the finer and less varied deeper-water sediments are found in the inland area. Volcanic 
activity was especially rife along the sea-coast of this Palaeozoic land, as evidenced by the 
greater development of contemporaneous igneous rocks in the sedimentaries of the coastal 
belt than in those of the inland area. 

After the laying-down of the Waipapa rocks, elevation ensued, and, partly as a result of 
folding, partly owing to subaerial deundation, the Waipapa rocks were separated into two 
upland areas by a broad trough running east and west. A long period of gradual, but per- 
haps interrupted,* depression, lasting from Late Mesozoic times through the Early Tertiary, 
then ensued, during which the Kaeo Series of generally shallow-water deposits accumulated 
in the trough and in the area to the south of the southern ridge of Waipapa rocks. 

The complex mass of Waipapa and Kaeo rocks was then elevated and subjected to sub- 
aerial denudation, so long continued that the land-surface was partially reduced to base- 
level. There occurred, probably at two quite separate times during this elevation, a wide- 
spread injection of both series with dykes of semi-basic and basic igneous rocks, which were 
in some cases accompanied by metalliferous solutions. Igneous rocks belonging to the later 
of these two periods of vulcanism reached the surface in the north-western corner of the sub- 
division, where the remains of a series of considerably decomposed breccias and lava-flows 
are found along the sea-coast. 

In Miocene times, after peneplaination of the old Waipapa and Kaeo land-surface had 
been almost completed, moderate depression took place in the northern part of the subdivision ; 
and, probably in great part in .the shallow sea so formed, the products of another series of 
paroxysmal eruptions accumulated. Moderate elevation, possibly accompanied by local 
faulting, then ensued, and the land was again subjected to subaerial denudation, by which 
possibly a part of the newly formed Wairakau Series had already been removed and partial 
peneplaination effected, when a renewal of volcanic activity flooded the land-surface with the 
widespread flows of doleritic rock which form the Kerikeri Series. During the extrusion of 
the Wairakau and Kerikeri rocks, the older sedimentaries were, in many places, intruded by 
dykes of andesitic or doleritic nature. 

Following Kerikeri times, the new land-surface was further elevated — probablv rather 
by differential faulting than by regional uplift. The streams, flowing over the heightened 
land-surface with renewed activity, cut through the sheet of igneous material in the west, 
where it was thinnest, and, entering the softer sedimentaries below, rapidly excavated deep 
valleys. The dissected land then subsided, and the sea advanced far up the vallevs, pro- 
ducing the irregular coast-line of the present day, with its drowned river-vallevs and out- 
lying reefs and islets. 

Volcanic activity on a minor scale probably continued to manifest itself intermittently 
in the south-eastern portion of the subdivision until comparatively recent times. Explosion- 
craters and scoria cones were formed, and lava-flows caused considerable local modification 
of the drainage. The Ohaeawai Hot Springs represent the d}-ing stages of this last period of 
vulcanism. 

It seems just possible that comparatively recently a slight elevation has occurred, but 
on this point the writers feel somewhat doubtful. 

General Account of the Structure of the Several Formations. 
The rocks of the W^aipapa Series have been subjected to repeated disturbances of an 
intense character. As a result, they are so profoundly jointed, faulted, and brecciated that 



* The distinctly Mesozoic and Tertiary characters of the fossils of the lower and upjaer portions respectively 
of the Kaeo Series indicate the possible existence of an unconformity separating the series into Mesozoic and 
Tertiary parts. 



23 

the determination of the original planes of stratification is sometimes impossible, and nearly 
always a difficult matter. Despite the great dislocations which these strata have undergone, 
schistositv is rarely developed. Subsequent intrusions by igneous rocks have resulted in 
local alteration and mineralisation, with the formation of insignificant deposits bearing 
manganese, gold, silver, and other minerals. 

The beds of the Kaeo Series, as a rule, dip at moderate angles and show but little altera- 
tion. In certain localities, however, the Kaeo rocks are nmch hardened and impregnated 
with silica, which" somewhat rarely is represented by definite veins ; elsewhere the intrusion 
of the Kaeo Series by basic igneous rocks has resulted in the permeation of the strata by copper- 
bearing solutions and the consequent formation of cupriferous zones. 

Since the deposition of the Wairakau Series no great folding has occurred, though rather 
extensive faulting of the beds has taken place. 

The two most pronounced faults of post-Wairakau times occur along the northern bunks 
of the Pirau and Waitangi streams, and may be known as the Pirau and Waitangi faults, 
respcctivelv. Both have a general E.N.E. and W.S.W. direction, and die out altogether near 
the middle of the subdivision. 

The Pirau fault has its ma.xinuim throw near the western boundary of the subdivision, and 
very possiblv exhibits greater tlisplucemcnt beyond the limits of th<' area under considera- 
tion. The throw of this fault nmst be at least 500 ft., judging by the relative levels of the 
Kerikeri How rocks at the trigonometrical stations of Takapuwahia (*1,457 ft.) and Te Puru 
(930 ft.). Besides the Kaeo and Kerikeri series, the Waipapa rocks are also visibly affected 
by the Pirau fault, forming on the northern (upthrow) side the prominent Mokau-Pirau system 
of ridges (thinly capped in one or two places by the remains of Kerikeri lava-flows). 

The Waitangi fault has its maximum throw at the eastern boundary of the subdivision, 
though whether it extends nmch east of this has not yet been proved. The downthrow is 
towards the south and probably amounts to fully 300 ft., as measured by the relative heights 
of the Kerikeri flow rocks on the Wainuite Plain and on the tableland north of the Waitangi 
River. In this case the only rocks involved are those of the Kaeo and Kerikeri series. 

Near the western end of Tauranga Bay the base of the Wairakau breccias is below sea.- 
level, and the series is in close pro.ximity to, but not visibly resting on, the Waipapa rocks, 
while about two miles to the east it is found resting on the Waipapa rocks at several hundred 
feet above sea-level. The supposition of a fault* striking in a general way north and south 
(thus coinciding with the main trend of Whangaroa Harbour), and ha\ing a downthrow to 
the west, would .satisfactorily explain this difference in level, and would also account for the 
discrepancy in the altitude of the base of the breccia at Moses Bay (sea-level) and at St. Paul's 
(500 ft.) It must, however, be remarked that, as explaiiu'd in Chapter W (page 51), the 
tufls miderlying the breccia on St. Paul's may possibly belong to the Wairakau Series, and 
not, as considered more likely by the writers, to the older Kaeo Series. If the former view 
as to the age of the tuffs prove the correct one, the evidence for faulting in the upper part 
of Whangaroa Harbour will be much weakened, but the probability of a fault in the neigh- 
bourhood of Tauranga Bay remains unaffected. 

Local chemical changes have also taken place in the Wairakau and Kerikeri rocks, of 
which the most interesting results are the formation of opal, and the leaching-out of iron from 
the volcanics, with consequent formation of limited beds of iron-ore. 

The later volcanics and unconsolidated debris are unaltered, save for the slight decompo- 
sition effected by subaerial agencies. 

The beds of the post-Miocene Ngawha Lake basin have, however, become impregnated 
m places, owing to solfataric activity, with sulphur, cinnabar, native mercury, bituminous 
materials, and other minerals. 



* Marked as the Whangaroa fault on the map. 



u 



CHAPTER III. 



PHYSIOGRAPHY. 



the Faulted Tableland 


.. 28 


(/.) Low-lying Alluvial Flats 


.. 28 


The Shore -line 


.. 29 


The Drainage-channels 


.. 32 


Fresh-water Basins . . 


.. 33 


Swamps 


.. 36 


Springs 


.. 36 


(a.) Soda Springs 


.. 36 


(b. ) Sulphur Springs 


.. 37 



Page ' Page 

Introduction . . . . . . 24 The Land — continued. 

The Land .. .. .. ..25 (e.) Plains of Different Origin from 

{a. ) The Faulted Tableland . . 25 . _ . . . . 

(b.) Re.sidual Hills or Monadnocks 
rising above the Level of the 
Faulted Tableland . . . . 27 

(c.) Isolated Hills of Wairakau, Keri- 

keri, and Later Acid Vokanics 

rising above the General Level 

of the Fatilted Tableland .. 27 

{d. ) Cones of the Later Basic Volcanics 

near Lake Omapere . . 27 I Man's Influence on the Physical Features 40 

Introduction. 
Like almost everv other part of New Zealand, the Whangaroa Subdivision exhibits remark- 
able physical features. The main part of its land-surface is a faulted tableland, deeply 
dissected bv numerous branching streams, and with volcanic cones rising in places above 
its general level. The deeply indented shore-line is of great beauty, c*nd one typical of the 
edge of a recently depressed land-surface. 

The varied peculiarities in the form of the land-surface and of the shore-line have been 
produced by folding and faulting movements and by erosive agencies acting on a somewhat 
complicated rock-structure. 

The sedimentary rocks of the highly folded coastal portion of the Waipapa Series and 
of the much disturbed but less crumpled Kaeo Series are usually soft and easily weathered. 
The Waipapa rocks in the interior, being more massive than either the coastal Waipapa rocks 
or the Kaeo rocks, are consequently more durable : while the igneous rocks of various ages 
form resistant material wherever they occur. 

The land has seen many changes of level. It is probable, as mentioned in Chapter II 
(page 22), that, at any rate in the northern part of the subdivision, the old surface of Waipapa 
and Kaeo rocks was almost completely base-levelled prior to the deposition on it of the Wairakau 
lavas and breccias, and was subjected to renewed peneplaination in the interval which elapsed 
between Wairakau times and the extrusion of the Kerikeri volcanics. Following this second 
period of peneplaination a great portion of the area was covered by the lavas of the Kerikeri 
Series, which filled up any depressions remaining on the surface of the peneplain. 

The tectonic movements which succeeded the la\-ing-down of the Wairakau and Kerikeri 
rocks elevated the peneplained surface largely shrouded by volcanics, and thus produced a 
tableland. This elevation was apparently not an even upward tilt towards the interior, 
but a lack of uniformity in the surface of the tableland was produced by block-faulting. With 
elevation, erosive acti\nty was increased, and a cutting-down of the land towards a new base- 
level began. Everywhere the tableland has been deeply dissected — to a late mature stage 
where the softer sedimentary rocks alone are present, or at least predominant, and where 
sculpturing of the valleys has been continuous since pre- Wairakau times ; to a less mature 
stage where the hard and resistant Wairakau and Kerikeri volcanics appear, and where the 
entire dissection has taken place since these were extruded. 

After the sculpturing of the land was considerably advanced, there occun-ed a moderate 
depression. Since this depression, only sufficient time has elapsed for the evolution of a 



PLATE VI. 

^^au'l^;at■lllieIlli. 




.-■Iff- 



Mdk 



MiT^wr iMTrifi 



'1i 



llr.AU OK W M.\N(;.\ii(i.\ ll.MiiiDLi! A r low I'idb. 
Shows pniMiMiiitophorcs of iiiMiimovcs in foicground. 





'^hk. 







Whaauahu.\ luw-vs-iiir A>"D St. Paul's. 



Itlllhin, \n. s.] 



[Fare p. 2/f. 



25 

youthful stage of shore-line development along the new sea-margin. During, and in part since, 
the dissection of the surface of the tableland, volcanic activity was renewed in the southern 
part of the subdivision. On this account the coiififruratioii of the land in this part of the 
area differs from that of other portions. \'alleys have been clogged, a lake formed, lava 
and scoria cones have risen above the older denuded surface, and numerous small ex- 
plosion-craters have broken out and siibs(>(|uently been filled with wate?' to form ponds. 

The L.\ni). 

The land mav be considered to display at the present day the following more or less 
distinct features : — 

(flf.) The faulted tableland, consisting in small part of an old penephiined surface, and 
in greater part of the peneplained surface shrouded in Wairakau and Kerikeri volcanics. The 
tableland, owing to relatively unequal uplift, has been l)l()cked into several flat-topped areas 
not of uniform height^ 

(b.) Isolated peaks, which rise above the level of the faulted tableland, and were monad- 
nocks, or residuals of erosion, at the time of formation of the peneplain. 

(c.) Isolated hills of Wairakau, Kerikeri. and later acid volcanics, rising al)ove the general 
level of the faulted tableland, and .seemingly representing old plugs or necks. 

((/.) Coues of the later basic volcanics, near Lake Omapere. 

(e.) Plains of different origin from the faulted tal)lelan(l. 

(/.) The low-lving flats near the mouths of the various streams, re])rcscntiiig in great part 
the result of erosion of the faulted tableland towards a jiew base-level, but partly formed by 
deposition of gravel and silt in the sea. 

(a.) The Faulted Tuhleland. — The faulted tableland consists of three principal flat-topped, 
or practically flat-topped, areas or blocks partially separated by faults.* The three all formerly 
stood at the sanu^ general level, but now, owing to movements which differed in degree rather 
than in kind, parts of them stand relatively at three discordant altitudes. The lowest part 
of the tableland is situated in the south block, and the highest in the north block. The middle 
block is separated from the south block by the VVaitangi fault on the south, and from the 
north block by the Pirau fault on the north. All three blocks apparently slope downwards 
to the east. Near the headwaters of the Kerikeri River the north and middle blocks 
stand at the same level, but a marked discrepancy in altitude is seen between this level 
and that of the eastern side of the southern block, which stands in general quite .'JOO ft. 
lower. Again, towards the western margin of the subdivision the north block rises 
fullv oOO ft. higher than the south-western extension of the middle l)lock, this discrepancy 
decreasing towards the east. The general level of the middle block, of the eastern part of 
the northern block, and of the western part of the southern block varies from 700 ft. to 900 ft. 
The greater part of these poitions forms the monotonous expanse known as the K<'rikeri 
Plains. The depressed ea.stern part ol the southern l)lock composes tlie relatively lertile fields 
around Waimate North ; while the western part of the northern block presents to the 
south the so-called Mokau and Pirau ridges, which comprise the highest land in the 
subdivision. 

The open, practically level surface of the tableland is still ])reserved in many parts of 
the subdivision — notablv in the Kerikeri Plains, which occupy the eastern and central portions 
of the subdivision north of the VVaitangi. In the south-western portion of the subdivision 
the surface of the pre- Wairakau peneplain, without a covering of volcanics, is preserved in 
the low ridges on either side of the old Ngawha Lake basin. 

♦ See Chiki)t.T II, |i. 23. 



26 

In the western and middle ])arts of the subdivision the middle and northern blocks of 
the tableland have been deeply incised by the tributaries of the Waihou, Kaeo, Pupuke, and 
Takakuri streams, their original surface being represented only by the highest crests of the 
ridges between the numerous valleys. 

In approaching the sea to the north, the northern block of the tableland descends abruptly 
in cliffs or steep slopes to the water's edge, except close to the mouths of the numerous streams 
where flood-plains occur. 

Relief of the land is naturally more conspicuous towards the sea, where the erosive action 
of the streams has been greatest, than towards the interior, where, since much of the area 
lies along the main divide between the east and west coast drainage, stream-erosion has been 
less intense. Relief above the general level of the tableland in the interior is, however, to 
be seen in certain residual peaks of the harder Waipapa rocks, in the scoria cones of the latest 
basic eruptives, and in certain hills — supposed to represent plugs of the Kerikeri volcanics. 
Sinc^e these hills surmount, rather than form pai t of. the blocks of the faulted tableland, they 
will be described in another part of this chapter. 

Where the dissection of the faulted tableland has been entirely in sedimentary rocks, the 
ridges descending from its surface, either to the sea-shore or to the level of the valley-floors, 
exhibit a very subdued topography, ledges of solid rock being almost or quite absent, and the 
whole surface covered with creeping waste of local origin. The ridges are generally well 
sculptured into numerous irregular branching spurs of usually rounded, but sometimes fairly 
sharp, crest-lines. This topography is to be seen typically along the sea-shore near Tauranga 
Bay, along the south-eastern shores of Whangaroa Harbour (see Frontispiece), and in the 
country lying between the Pupuke and Takakuri streams. 

The high land between Taupo and Tupo bays, composed of hard basic and semi-basic 
igneous rocks associated with the old sedimentaries, though it rises steeply from the sea- 
shore to the relatively high altitudes of 400 ft. to 800 ft., exhibits few pronounced rock-ledges, 
and shows an evenly graded rise from base to summit. 

Where the sedimentary rocks are surmoimted by volcanics (mainly of the Wairakau and 
Kerikeri series) the smoothed slopes rise gradually from the base-level to the bottom of the 
volcanic rocks, when not infrequently sharp cliffs of solid rock ascend to the top of the table- 
land. This feature is well seen along the northern bank of the Waitangi River, along the 
eastern side of Upokorau Creek (Plate III), in the castellate dome of St. Paul's near Whangaroa 
Harbour (Plate VI), and in the outstanding peak of Taratara (Plate X). The crest of the 
latter rises, on the north side, from the rolling clay gum-lands in two great steps of Wairakau 
breccia. The top is flat and mesa-like in appearance. 

WTiere the descent from the faulted tableland-top to base-level is entirely in volcanic rocks, 
cliffs are pronounced and common, and are sometimes of considerable height. This topo- 
graphy is seemingly the result of the very resistant nature of the rock, of its tendency to regular 
jointing, and possibly of the sudden uplift of the country after the Wairakau volcanics were 
laid down. It is apparent only where the volcanics have been deposited to a great thick- 
ness, as near the mouth of Whangaroa Harbour, and north-westward from Whangaroa 
Heads to Taupo Bay. This very abrupt phase of topography is magnificently exemplified 
in the splendid cliffs of volcanic breccia — 400 ft. or more in height — which border Waihi 
Bay (Plate VIII) and the southern side of Okamoko Bay (Plate IX), on Whangaroa Har- 
bour, and on the open coast-Une just outside W'hangaroa Heads. Almost everywhere, save 
on the outer coast, where washed by the waves of the open Pacific, the cliffs descending 
from the tableland are relieved at their bases by slopes of debris, generally overgrowni with 
vegetation. In some places, as in the inner part of the harbour, just south of the settle- 
ment of Totara North, these slopes ascend without precipices to the very top of the tableland. 
The hill of St. Peter's, on Whangaroa Harbour, which shows Wairakau breccia from the 



27 

water's edge to the top, exhibits even slopes without declivities, save on the relatively 
inconspicuous dome forming the topmost hundred feet. 

The surface of the several blocks of the faulted tableland, being almost devoid of high 
timber, and clad only with a vegetation of scant manuka, offers a ready means of comnuinica- 
tion from place to place. Paths lead in every direction across the Kerikeri Plains, and along 
the crests of the ridges between the various streams. Owing to the general infertility of the 
soil, the tableland, notwithstanding its open nature, has been but little cultivated, save at 
Waimate and Okaihau. 

(b.) Residual Hills or Monadnocks rising above the Level of the Faulted Tableland. — When 
the land had almost reached base-level, before the Wairakau volcanics were deposited, certain 
peaks and ridges, either from superior hardness or from some accident of situation, were left 
above the general level, forming; residuals of erosion or nu)nadiu)cks. Some of these were 
not completely shrouded by the Wairakau and Kerikeri volcanics, and are to be seen rising 
al)ove the level of the several blocks of the faulted tableland. Of such nature are the conical 
peak of Whakarara (1,082 ft.), composed of hard i|uartzitic rock of the \Vaipa])a Series, and 
bordered on the south by volcanics, and the hills I'arahirahi (l,(K)() ft.) and Oikiira (1.087 ft.), 
in the southern part of the subdivision, composed of Kaeo rocks. 

Several residual hills surmount the hijih western portions of the most northern bhjck of the 
faulted tableland on the Mokau. Piiau, and Manj^akino ridjics. TIk' most lofty of these, an 
unnamed point on the Pirau Ridge, rising to a height of 1. 7")] ft., is the hiiihest hill in the 
subdivision. 

(c.) Isolated Hills of Wairakau, Kerikeri, and Later Acid Volcanics rising above the General 
Level of the Faulted Tableland. — At a number of points on the faulted tableland, low hills of 
Kerikeri or Wairakau volcajiic material rising above the jieneral level are probably the necks 
of lava cones or some hard renmant of a cone in the case of the lava hills, and a plug of agglome- 
rate filling a volcanic neck in the case of the breccia peaks. Trigonometrical stations A ( 1 , 1 95 ft.) 
and H (1,177 ft.), in the Omapere Survey District, are .seemingly the necks of lava cones. 
Higher points of breccia, which are possibly necks of old cones, are Tehe o Riri, Akaterere, 
Patukohatu, and Orotere. These various hills of volcanic material, rising higher than the 
general level of the faulted tableland, almost invariably exhibit distinct ledges of solid rock, 
but smooth, well-graded slopes are in general more conspicuous. 

The rhyolite mound of Putahi (Plate IV) shows a few ledges of solid rock on its slopes, 
but in general both the hill itself and the slopes descending therefrom are smoothed. At 
many points towards the summit of the hill occur narrow shaft-like holes, apparently old 
steam-vents. Many of the holes are shallow, but some are 'M) ft. and more in depth. One 
hole, which has been used by the Maoris for generations as a burving-pit, is at least 100 ft. deep, 
and possibly much more. 

{d.) Cones of the Later Ba.fu- Volcanics near Lake Omapere. — The later basic volcanics 
are not widely distributed in the Whangaroa Subdivision, and consequently there are but few 
well-preserved cones in the area. The hills being comparatively youthful, their slopes have not 
yet all reached grade, and exposures of solid rock are generally common. 

By far the most prominent cone is Te Ahuahu (1,240 ft.), (Plate I\'), composed of scoria, 
which rises close to the shores of l.,ake Omapere, and forms a conspicuous hill about 500 ft. 
above the general level of the middle block of the tableland. Te Ahuahu exhibits a fine 
crater on its summit, which is breached on the western side. The slopes rise from the table- 
land-level at an inclination of about 15°, the angle increasing slightly towards the top. Not 
far south of Te Ahuahu are Maungakawakawa (Plate IV) and Waimimiti, much more dissected 
cones, probably intermediate in age between Te Ahuahu and the volcanics composing Tarahi 
Ridge. The latter — a group of hills that rise somewhat abruptly behind the Ngawha Settle- 
ment, and slope more gradually towards Lake Omapere — represents the more or less dissected 



28 

remains of a iiurtiber of volcanoes belonging to the older portion of the later basic volcanics and 
the flows therefrom. Another scoria cone is Kaikohe Hill, which rises only about 100 ft. above 
the general level in this locality. However, this general level is somewhat below that of 
the tableland surface, and represents a plain belonging to the class described in the next 
paragraph. 

(e.) Plains of Different Origin from the Faulted Tableland. — These plains are either the 
result of the actual filling, by newer volcanics, of the valleys cut in the tableland surface, or 
represent, in one instance, a sediment-filled lake-basin produced by the damming of streams 
either by the earliest manifestations of the later basic eruptives, or more probablv by the Keri- 
keri lavas. The fertile plain of Kaikohe and that to the east of Te Ahuahu, filling the valley of 
the Ukokako Stream, are of the first nature ; while the example of the second class is to be 
found in the flat country of the old Ngawha Lake basin round the Ohaeawai Hot Springs. 
In this locality the old drainage towards Ngawha Settlement was dammed either by the lava- 
flows from the volcanoes forming Tarahi Ridge, or more probably by Kerikeri lavas (of which, 
however, few traces now remain), and two new outlets were finallv made further towards the 
south. After the filling of the lake by sediment, marshy spots remained at many places on 
its surface, and later developed into peat swamps. Afterwards explosion-craters broke out at 
man\ points in the basin, and some of these are now occupied by ponds, described latei' in this 
chapter. 

(/.) Low-lying Alluvial Flats. — The alluvial flats are fomid at the mouths of almost all 
considerable streams in the area, and, in the case of the larger streams, extend for some dis- 
tance up their valleys. The flats are, however, not entirely the product of fluviatile erosion and 
deposition, since their areas are being augmented outwards in at least two other ways — namely. 
by the insilting of the mangrove swamps and by the advance of sand-dmies from the coast. 
In the Whangaroa Subdivision mangrove swamps of any size occur only inside the Harbour 
of Whangaroa — at the mouths of the Kaeo, Pupuke, and Waihapa streams. Inconsider- 
able swamps are found at the mouths of smaller streams flowing into Whangaroa Harbour 
and on Tauranga Ch-eek, which enters the sea just east of Whangaroa Heads. The sand accu- 
mulating in the somewhat sheltered bays of Taupo, Tupo, and Tauranga is being swept inland 
bv the wind, and is forming dunes. 

The alluvial flats in nearly all the streams are long and narrow. They are occasionalh- 
surmounted by residuals of erosion produced by the wearing-away of portions of the table- 
land. Such a residual is Pohui, in the alluvial flat of the Kaeo. 

The true alluvial fiats, or relatively extensive stretches of flat-lying land, seldom reach 
an altitude of more than 200 ft. above .sea-level, but in some instances narrow rims of alluvial 
land border the streams to greater heights. 

The flood-plains of the Kaeo and the Pupula' lurni the must extensive areas of alluvial 
flat in the subdivision. These flats extend up the Kaeo for nine miles and a half from its 
mouth, and have their greatest width — .some 60 chains — near the Settlement of Kaeo. The flats 
along the Pupuke are smaller, continue up the stream for some five miles only, and are never 
much more than 20 chains wide. 

In addition to those already mentioned, flats are to be found along the Waihapa, Waitapu, 
Takakuri, Whakateterekia, Waipapa, Whakanekeneke, Utakura, and Waitangi streams. 

The alluvial flat of Taupo Creek is remarkable in that it is almost as broad as long, being 
about 75 chains in length and about 50 chains in width at its mouth. This apparent excep- 
tion to the usual long and narrow flood-plain is easily explicable when it is realised that a 
great part of this area represents a prolongation of Taupo Bay filled in by the aggrading action 
of the sea and of Taupo Creek. 

Low terraces are occasionally to be seen surmounting the flood-plains and bordering the 
edges of the spurs descending from the tableland. Remains of high-level terraces are found 



29 

near the mouth of Tangitu Creek and elsewhere towards the head of Pupiike River, and on 
the Whakanekeneke and Waikaraka streams. 

The alluvial flats of the principal valleys, owino; to their dense vegetation and swampy 
soil, were generally avoided as routes by the early settlers, and it is only of late years that 
roads have been formed on them. 

The Shore-line. 

The shore-line of the Whangaroa Subdivision well exemplifies the effect of relatively recent 
depression on an area exhibiting in general a subdued topography and a mature drainage- 
system. The well-embayed coast, the sunken stream-mouths, the numerous rock-girt islands, 
and many other features indicate that the shore-line is still very young ; but that it is not abso- 
lutely infantile is shown by the production of rock-benches and allied features, and by the filling- 
up of the bay-heads by the development of barrier beaches or by river-insilting, aided by the 
advance of mangrove swamps. 

The shore-line of the Whangaroa Subdivision extends from the western side of Tupo 
Bay to about a mile east of the mouth of the Tangaire Stream. Measured iJlong the numerous 
sinuosities, the shore-line in this distance is at least forty-nine miles long, though in a straight 
line the eastern and western limits are not more than 1 2.1 miles apart. 

In general, the coast presents a .series of bold forelands, .separated by sandy or gravelly 
bays. According to the nature of the rocks, the forelands may be either high and almost 
vertical cliffs, or they may be steep but graded slopes, broken by low cliffs at the sea-margin. 

What little is known about the island shelf from which the bold coa.st rises is to be 
gathered from the Admiralty chart, from which the submarine data of the detailed map of 
Whangaroa Harbour have been ol)tained. The southern extremity of Stephenson Island 
lies some three miles and a quarter from the North Head, at the entrance to Whangaroa Har- 
bour, and in this distance the deepest sounding is only 16 fathoms. The soundings show only 
gravel, sand, and broken shells, but it is probable that solid rock is relatively close beneath. 
In a direction at right angles to the coast-lim- the iOO-fathom line is about si.xteen miles distant 
from the entrance of Whangaroa Harbour. The comparative remoteness of that submarine 
contour indicates graphically how gradual is the shelving of the sea-bottom. 

Embayments in the .shore-line occur at many places along the coast, '{"he .splendid 
harbour of Whangaroa is nmch the most notable, but, .since it represents a somewhat special 
feature, it will be left for later discussion. The most important of the other embaymejits 
are Tupo, Frear, Camp, Taupo (Plate VIII), Taurani;a, Kairauwaru, Wahinepua, Mahinepua, 
Wainui, and Tangaire bays, all of which present many features in common. All show beaches 
usuallv composed entirely, or almost entirely, of sand, but in some cases of boulders, cobbles, 
and gravel, as the beach of Kairauwaru and other bays. 

Streams enter all of the bays mentioned, and nearly every cove along the very irregular 
shore-line of the older sedimentary rocks. In places several brooks representing the dis- 
membered drainage of one and the same ancient stream enter the same bay. Ordinarily the 
streams are deflected from the western side to the eastern side of the bay, their course flowing 
parallel, or approximately parallel, to the beach. This deflection is especially noticeable in 
Taupo and Tupo bays. * 

In places the smaller creeks enter the .sea in falls over rock declivities, having becm 
betrunked by cliff -retreat. 

Dunes formed from the sand, driven shoreward by the waves and currents, form barrier 
beaches in many bays, as at Taupo, Tupo. Tauranga. and Wainui bays, and in some cases 
dam Vjack marshy stretches of land. 

Mangrove swamps, though frequent in Whangaroa Harbour, are rare on the open coast. 
A snxall mangrove area occurs near the mouth of Tauranga Creek. 



30 

DifEereiice in the structure of the rocks fronting the ocean causes very marked dissinii- 
laritv in the character of the headlands. Ordinarily, where the old sedimentary strata, with 
the included igneous rocks, appear, the shore-line is extremely irregular, with steep slopes 
and relatively siiiall but abrupt cliffs at the water-margin ; while, where the Wairakau 
volcanics conie to the water-front, a less irregular shore-line and much loftier and almost 
vertical cliffs are apparent. North of Whangaroa Heads the cliffs of Wairakau breccia 
are of magnificent proportions — mural precipices rising 300 ft. or 400 ft. straight from the 
water's edge. These are especially remarkable at False Head, where they form a bold and 
striking landscape. 

Rock-benches are developed in many places along the steeper parts of the shore-line, 
more commonly in the sedimentary rocks, but also in the volcanics. These benches consist 
of shelves cut out in the solid rock, generally horizontal, or nearly so, and not infrequentlv 
surmounted by skerries, or pinnacles of harder material (a dyke of igneous rock or a bit of more 
resistant sedimentary strata), which was not so easily eroded by the waves as the main mass 
of the shelf (Plates VII, VIII, IX). The shelves vary in width from a few feet to 50 yards 
or more, and may be continuous along the coast for 200 or .300 yards. In places the surface 
of the shelves is absolutely flat, save for the minor pitting of the rocks. Elsewhere it has 
a very slight slope seaward. Not infrequently the shelf is dissected into a number of tabular 
blocks by deep channels, of course containing water. The inner margin of the shelves cor 
responds with the base of the cliffs. As a rule, the benches, save at their innermost border 
are covered with water at high tide, but in places they rise a little above ordinary high-water 
level. Usually the rock-benches are more common in the less exposed places than at the 
headlands. The most remarkable rock-benches are those occurring just west and east of 
Taupo Bav (Plate VIII), and just east of Pa Island. The benches at the latter place have a 
maximum width of not less than 50 yards, and the flat surface stands in places some 9 ft. 4 in. 
above the level of low tide. The bench at the edge of the narrow channel separating Pa Island 
at high water from the mainland is especially noteworthy, exhibiting a flat shelf several chains 
wide, and closely resembling a road-cutting. 

The significance of these rock-benches, which are of wide distribution throughout the 
northern part of New Zealand, is not clear. If their flat surface be interpreted as a plane 
of marine erosion, then the fact that this surface at present stands above the sphere of action 
of the waves, except, perhaps, at high tide, would indicate that elevation of a remarkably 
uniform amount has taken place over a very considerable area. However, other evidences 
for such elevation are either absent or of an unsatisfactory character. Moreover, it seems pos- 
sible to ascribe the formation of the rock-benches to the co-operation of subaerial weathering, 
which causes the retreat of the cliffs, with marine transport, which removes the waste so formed. 
If this interpretation be the correct one, the rock-benches of the North Auckland Peninsula give 
strong support to the view* that marine erosion (except in the most exposed situations, where, 
as already noted, rock-benches are inconspicuous or absent) is usually unable to keep pace 
with subaerial. 

Sea-caves, worn by the waves at the base of the cliffs, and narrow chasms, into which the 
water rushes at all states of the tide, are common along the coast. The caves in the neigh- 
bourhood of Whangaroa Heads, and those on the landward side of Pa Island, are good and 
typical examples. 

Rock arches sculptured out of outstanding ribs of solid rock form picturesque features 
here and there along the coast. Of this nature are the " Hole in the Wall," just west of 
Whangaroa Heads, and the arches about half a mile west of Pa Island and on the outer side 
of Stephenson Island. 



* A. Geikie, " Text-book of Geology," 4tb ed., voL i, p. 573. 



PLATE YII. 



L. 




C'oAsr NKAK .M.\}|im:i'1" A I5ay ai IIii;ii i'lDi;. 
Shows ()iitlviii;j; skciiii's ,niil islands and small rmk Ix'nchcs. Cavalli Islaiiils In distance. 




SlIoliK-I.INK Ol' !■ I.AI' IsT.AXI). 
Low cliffs of licxagonally jointed dolerile. irxegiilar bench of the underlying iiioie vesicular flow. 
/iiil/ifin Xo. S.] [Fare. p. .ii). 



31 

When flat, or nearly flat, rock-benches are absent, the sea- bottom descends in places abrui)tl\- 
from the shore-line : in other places the descent is more gradual, with skerries, stacks, or 
small rocky islets just off the land. Some of the islets are land-tied at low water, as Pa Island, 
which is connected with the mainland at the lowest tides by a narrow sand isthmus. The 
islands lying off the mainland, if Flat Island and Stephenson Island be excepted, are all small 
and rocky, and generally very rugged and irregular in outline, with steej) slopes oi- cliffs 
descending to the water's edge. Cone Hock, Oruateiuanu Island, and Arrow Rock are the 
most conspicuous. 

Stephenson Island, which lies from three to four miles off the coast, is about two miles 
long by nearly three-quarters of a mile wide at the south-eastern end, where widest. Several 
smaller islands appear in places around its shore-line. With the exception of three or four 
gravelly 'bays on the sheltered side, the rocky shores rise abruj)tly. and on the exposed side 
precipitously, from the water's edge to a height of 200 ft. or 300 ft. 

Flat Island and the smaller neighbouring island of Motuekaiti are somewhat different 
in character from Stephenson Island. They both show an even crest-line, and are flat and 
mesa-like in appearance. Flat Island is a little le.ss than 100 ft. high, and Motuekaiti just 
a little higher. They are composed of two nearly horizontal flows of lava, visibly super- 
imposed in the case of Motuekaiti on a basement of older sedimentaries. The coarser-grained 
lower lava-flow weathers into gradual slopes : while the upper and finer-grained How, owing to 
its columnar jointing, is denuded into low vertical cliffs (Plate VII). Thus the island shows 
abrupt declivities at the top, relieved by gradual slopes below, with insignificant cliffs or a 
boulder-strewn shore at the water-margin. The boulders are fornu^d by the rounding, through 
weathering, of the jointed lava-fragments. 

Whangaroa Harbour (sec detailed map) forms one of the most spacious and perfectly 
land-locked shelters in New Zealand. It owes the peculiarity of many of its main features 
to the fact that the river-valley of which it is the depressed representative was eroded, pos- 
siblv along a fault-line, partly in a great thickness of Wairakau breccias and tuffs and partly 
in soft sedimentary rocks. 

The harbour trends approximately north and south. The principal entering-stream, 
the Kaeo, Hows into the harbour at its south-eastern end, and may be considered as the trunk 
stream, which the other streams, now entering the harbour, and dismembered by depression, 
joined prior to that event. Not only have all the streams been betrunked, but some — namely, 
those entering the north side of Okamoko Bay — are beheaded as well by the cutting-back 
of the cliffs facitig the open sea. 

Towards the head of the harbour, where dissection by the larger streams has removed the 
covering of volcanic material, the slopes descend to the shore-line with gentle gradient, but 
towards the mouth of the harbour, where volcanics prevail, precipices, often relieved by talus at 
their bases, flank the water-front. The difference in the character of the rock explains the 
narrowness of the harbour-entrance and the width of the upper part of the inlet. 

The small islands of the harbour owe the variety of their forms to the rocks of wliicli 
thev are composed. Thus, Peach Island (Plate X). of volcanic material, is lofty and rugged, 
while the neighbouring land-tied Jones Island, of sedimentary rocks, shows very gentle 
slopes. 

Rock-benches are common along the shores of the mainland and of the islands. Red island 
is a mere pinnacle superimjiosed on a platform of rock, while other islets, such as Flat Rock and 
the reefs in Okamoko Bay (see detailed map), are practically worn away, and, being visible only 
at low tide, are shoals at high water. Round the base of the cliffs one sees various results 
of marine erosion — pinnacles, caves, chasms, and coves. The peculiar " Mushroom Rocks " 
in Ranfurly Bay — the name being explanatory of their appearance — are grotesque products 
of wave-erosion surmounting rock-benches. 



32 

Wide stretches of tide-iuarsh and mangrove swamp and extensive mud-flats, bare at low 
tide, at the mouths of the Kaeo, Pupuke, and other streams at the head of Whangaroa Har- 
bour show graphically the advance of the land. Old settlers tell of the rapid shallowing 
of the upper part of the inlet. In fact, everywhere along the shore-line the tilling-up of the 
inlets and the wearing-back of the headlands make evident the rather rapid ageing of the 
youthful shore-line. 

The average rise and fall of the tide in Whangaroa Harl)our is al)out 8 ft. at spring tides 
and ^ ft. at neap tides. 

Landslides occur in various places along the shore-line, both of Whangaroa Harbour and 
of the open sea, but are not very common or of large proportions. 

Whangaroa Harbour, being .so safe and spacious, was resorted to in the verv earlv whaling 
days by many small crafts engaged both in whaling and in the timber trade. Thus was 
established on the shores of the harbour the nucleus of a small settlement which later spread 
into the interior. 

The many sheltered inlets along the coast-line of the W^hangaroa Subdivision offer good 
shelter to-day to a few small hshing-boats. 

The Drainage-channels. 

As mentioned in an earlier paragraph of this chapter, the part of New Zealand now being 
considered had been well dissected prior to the recent depression. The dissection was highlv 
mature where sedimentary rocks alone occurred or predominated, but not so much so where 
the W^airakau and Kerikeri volcanics were most prominent. The depression of the land 
drowned the mouths, dismembered the lower tributaries, and by raising the base-level to 
which it is possible for the streams to erode their channels, hastened the ageing of the vallevs. 

The drainage in general is that which is naturally to be expected in an uplifted plain or 
tableland. It is insequent, or one which has cut down into the country in an irregular and 
branching way, independent of the inclination of the underlying rocks. .Streams cut in the 
sedimentary rocks all flow at grade, or at an angle approaching grade almost to their headwaters. 
In some cases waterfalls aiul rapids do not occur at all, even at the very top, where, in fact, 
• the streams often rise in swamps. Where, however, the streams flow through the hard rocks 
of the Waipapa Series, or through harder bands in the Kaeo Series, falls of considerable mag- 
nitude appear, as in the tributaries of the Waipapa River and in the tributaries descending 
to the Kaeo River from the Huia Hill. It is very prol)able that the greater elevation of the 
land north of the Piiau fault accounts in part for the high falls in some of the tributaries of the 
Waipapa. 

The drainage-channels cut in the volcanic rocks are remarkable in that they show stretches 
of partiallv graded course broken by waterfalls or rapids, as, for example, in the Puketotara, 
Kerikeri, and Takou streams, which are not entirely within the. limits of the subdivision ; in 
fact, the falls may occur, even in large streams, at sea-level, as in the case of the Kerikeri, where 
there is a 5 ft. or 6 ft. fall at the limit of the tide at low water. This fall is not the product 
of betrunking bv clif!-retreat. It is situated some miles from the open sea, at the head of a 
winding tidal channel produced by the retreat of the waterfall. The lack of complete grade 
in the streams flowing in volcanics is apparently due to the resistant nature of the rocks. 

The Waitaugi, the middle and upper parts of which lie within the subdivision, is maturely 
graded onlv in its middle course, where it flows in sedimentary rocks. Rapids or waterfalls 
occur in the upper and lower pails of its course, which are incised in volcanic material. Like 
the Kerikeri, the Waitangi enters the sea over a waterfall situated at the head of a sinuous 
tidal channel. A fine waterfall, about 70 ft. in height, is to be seen on the Utakura Stream 
not far below Omapere Lake, where the new stream is rapidly cutting towards base- level 
(Plate V). A beautiful forest-bordered gorge extends for some distance below the falls. 



PLATE VIII. 





TaUI'O JiAY .\|- Low TlDK. 

Shows oxtoiisive !()( k liciK h. Rocks in I'oroiji-ound are basal longlouieratcs of Kaco Sorios. Hills iii 
liackground are formed of Wairakan Breccia. 




glS?k 



Jl III/, fin \'K 8.] 



W.Uin JiAY, WlIANOAIiOA HaKHOUI!. 

Is boi-dered by cliffs of Waiiakau Breccia. 



[Fur, p. 32. 



38 

The upper part of the Utakura Stream forms an exception to the usual iusecjueut draiuai^e. 
The drainage was originally to the east, but the clogging of the valley by some of the most 
recent lava-fiows diverted it to the west, producing ol)se(|uent drainage. 01 similar nature 
are the streams draining the old Ngawha Lake basin, which formerly left the basin at the 
north-east end, but now flow out further to the south. The Omao and Te Ruatoa streams, 
occurring at the extreme south-west corner of the subdivision, are at present, with the retreat 
of the local divide eastward, capturing the upper waters of the Pakeretu Stream. Other 
examples of drainage-capture seem to have occurred on either side of the ill-defined, some- 
what sinuous main divide between Puketi and Lake Omapere. 

The small streams entering Okamoko Bay, in Wiiangaroa Harbour, in places show fulls 
at their mouths which are probably due to cl if!- retreat, through aerial, and possibly some- 
times marine, denudation. 

A rather remarkaljle change in the middle waters of the I'irau has taken place sinc<^ a 
great flood some forty years ago. Prior to that time the waterfall situated close to 
Te Puru Trigonometrical Station had a heiglit of 100 ft. At the time of the flood the counse 
was altered, a weak place in the lavas was found, and now the waterfall is only 25 ft. high, 
but it is 15 chains higher up the stream, and has, therefore, been retreating at the rate of 
over 8 yards per annum since the alteration. 

In the following table are given some particulars regarding the principal streams of the 
subdivision. The velocity, upon which the calculation of the discharge largely depends, was 
estimated as carefully as possible 1)V means of floats, .\lthough the results cannot be regarded 
as more than a rough approximation, they afford a fairlv reliable means of comparison between 
the different streams. 





Esitiinated 


Estimated 








stream and Appmxiniate 


Di»ohar(?e, 


Siirface- 








Leagtli 1 within Suhili- 


in Culjic 


velocity, 


When' iiit'H.-.iiml 


Dat. 


t'liiiditioii. 


vision ) . 


Keet per 


in Feet per 










Second. 


Second. 








Kaeo (13 miles) 


44 :.") 


1 .->:! 


()|iC<»ite Kaeo Hot'-l 


27/2/08 


.Slightly above normal 
for the time of year. 


Kerikeri (6 miles) . . 


9 22 


090 


At eastern boundary of .nub- 
division 


13/4/08 


Low. 


Puketotara (3} miles) 


1287 


099 


At eastern boundary of sub- 
divUion 


13/4/08 


" 


Pupuke (8 miles) . . 


54 OO 


2 70 


.\t mouth of .\waiti Creek. . 


13/12/07 


Slightly above normal 
forthe time of year. 


Utakura (7 J miles).. 


r)5-75 


223 


.\t western boundary of sub- 
division 


28/4/08 


Normal. 


Waihou (14 J miles. 


81-31 


2.34 


Just below junction of Wai- 


16/4/08 


,, 


measured to the 






papa and VVhakanekeneke 






head of the \\Tiak.i- 






rivers 






teterekia) 












Wairoro (2i miles) . . 


(109 4 
■( 300 


2-481 
17 


At southern boundary of sub- 
division 


( 16/6/08 
■( 1/3/09 


Swollen. 
Very low. 


Waitangi (6J miles) 


( !tj"8 
i 2002 


3-95 « 
1-57 . 


.At eastern Itoundary of sub- 
division 


1 9/6/08 
1 1/.3/09 


Normal (for winter). 
Very low. 



Fresh-water Basin.s. 

The fresh-water basins of this part of New Zealand are of two kind.s — namely, tho.se pro- 
duced by the damming-back of the waters of a valley by a lava-flow and tho.se that occupy 
explosion-craters, ver\' possibly of much the same character as that of the great Waimangu 
" geyser " of the Rotorua district. 

Of the first class, the only example, excluding the insilted Ngawha basiii, is J^ake 
Omapere, which has been formed bv the damming of the headwaters of the Waitangi. The 
3 — Whangaroa. 



34 

lake is two miles and three-quarters long from east to west, and about two miles wide from 
north to south. The depth is remarkably uniform, varying from 7 ft. to 9 ft., except along 
the water's edge, where naturally it is less. The lake-bottom is covered with 2 ft. or more 
of soft mud, a feature which, with its swampy shores, testifies to the insilting of the lake from 
the low surroimding hills. Submerged stumps of kauri and other trees in situ are exceedingly 
common, especially at the north- we.stern end of the lake. They would appear either to be the 
remains of the forest which covered the site of the lake Ijefore its formation or, less probablv, 
to indicate that the water of the lake once stood for a long period below its present level. 

Of the second class of water-basins, none is sufficiently large to be called a lake. Thcv 
are mostly small ponds, some ten in number, all in the neighbourhood of the Ohaeawai 
Hot Springs, in the flat country of the old Ngawha Lake basin (see detailed map). The largest 
pond. Waiparaheka. is 17 chains lonu and oh chains wide. Strangely enough, its greatest depth 
— 91 ft. 4 in. — is at the upper end, where a small stream enters from another pond known as 
Ngamokaikai. The latter is smaller than Waiparaheka, and slightly shallower, its greatest 
depth being 74 ft. 8 in. The water of Waiparaheka is milky with flowers of sulphur, but 
quite cold. The following is an analysis of a sample of the water of this pond : — 





Grains per Gallon. 


Sodium-chloride 


0-2 


Sodium-sulphate ) 


fi-fi 


Potassium-sulphate 1 


• . . . . \J ^J 


FeiTous sulphate 


0-4 


Calcium-sulphate 


0-7 


Magnesium-sulphate . . 


0-6 


Silica (SiO 2) 


0-7 


Free sxiiphuric acid (HjSO^) . . 


.. 201 


Free carbon-dioxide (CO2) 


.. 470 



Hydrogen-sulphide was present when the water was collected, but was lost by leakage, 

A sample of the gas which bubbles up violently all over the surface was found to have 

the following composition :- — 

Per Cent. 
Carbon-dioxide (CO 2) 



Hydrogen-sulphide (H2S) 
Methane (CH J 
Air, , 
Nitrogen 



Trace.* 
6-7 
1-9 
2-6 



1000 



The water of Ngamokaikai is clear, but gas-vents occur at the outlet of the stream flowing 
to Waiparaheka. 

Waiapawa Pond is almost round, anrl al)out 9 chains in diameter. Its bottom is prac- 
tically flat, with an almost uniform depth of about 14 ft. The water is clear and cool, but 
submerged gas-vents occur around the eastern side, Waiapawa, Ngamokaikai, and Waipara- 
heka are surrounded by fallen kauri-trunks in great number, and some of great size, embedded 
in peat. Apparently the sites of the ponds were occupied by peat swamps containing kauri 
timber before they were converted into ponds by explosions of gas and steam. 

Tuwhakino is about half the size of Waiapawa. Formerly the pond is said to have been 
of great depth, but owing to insilting since the opeuing-up of the mercury -.works it is now 



* The amount of hydrogen-sulphide is too small to be accurately determined, but probably amounts 
to about 001 per cent. 



86 



shallow, the greatest depth being only 17 ft. The water is clear and goiierally cool, though 
springs with an average temperature of about 27° C,* occurring on a small spit at its south- 
west corner, warm the water in the immediate vicinity. An analysis of the water of one of 
these springs is subjoined : — 

Grains 
per Gallon. 
Sodiiun-chloride . . . . . . . . . . 136-5 

Potassium-chloride . . . . . . 13-0 

Sodium-sulphate . . . . . . 

Calcium-sulphate 10 

Magnesium-sulphate . . 0-5 

Sodium-bicarbonate.. .. 71-4 

Ferrous bicarbonate . . 

Sodium-silicate '21 

Free carbon-dio.xide (f!0,) 3.o0 

Hydrogen-sulphide (HjS) ()-3 

Waitetera, a small pond only 2 chains wide and long, is very deep for its size, having a 
ma.ximuni depth of iO ft. Like W'aiparaheka, the water of the pool is white with flowers 
of sulphur, and exhibits a strong ebullition of gas, especially on the north and west sides. 
This gas was found to have the following composition : — 

Per Cent. 
88-7 
Small trace.l 



Carbon-dio.xide (CO2) 

Hydrogen -sulphide (HjS) 

Methane (CH^) 

Air 

Nitrogen 



6-3 
•J-7 
2-3 



The following is an analy.sis of the water :- 



1000 

Grains 

per Gallon. 

015 



Sodium-chloride 
Sodium-sulphate I 
Potassium-sulphate ) 
Ferrous sulphate 
Calcium-sulphate 
Magnesium-sulphate . . 
Silica (SiOo) 

Free sulphuric acid (H^SU^) 
Free carbon-dioxide 
Sulphuretted hydrogen (HjS) 

The pond is bordered in places by peaty material. Just 

which is a replica of the larger pond except that its water is <|uito cold, fias 

around Waitetera, while two small holes contain water at temperatures of 36'^ ('. and 22 ('. 

respectively. The temperature of Waitetera is 21° C.J 

A pool occurring on a branch of the Tuwhakino Creek, and three on a branch of the Manga- 
tawai Creek, are all sulphur pools resembling W'aiparaheka. The three pools on the branch of 
Mangatawai Creek have all been reduced in size by the cutting-back of the streamlet draining 



3-5 

0-2 
0-5 
0-6 
0-7 
20 
«50 
01 2 

above Waitetera is Little Waitetera, 
vents are common 



* Temperature of the air at the time of observation, 9-5° C. 
t The amount of hydiogen-sulphide is tO'O small to be accurately determined, 
X Temperature of air at time of observfit ions, 18° C. 
3* — Whangaroa. 



36 



thoin. The upper two originally formed one pond. The following is an analysis of the water 
from the upper of these two pools : — Grains 

per Gallon. 
0-2 



3-2 

014 
1-5 
]-5 
I -5 
4] 
520 



Sodium-chloride 

Sodium-sulphate | 

Potassium-sulphate j 
Ferrous sulphate 
CalciTini-sulphate 
Magnesium- sulphate . . 
Silica (SiOj) 

Free sulphuric acid (HgSO^) 
Free carbon-dioxide (COj) 

Hydrogen-sulphide was also present to a small extent when the samples were collected, but was 
lost by leakage. 

(Swamps. 

Owing to the impervious nature of the products of rock-decay in the Whangaroa Subdivi- 
sion, swamps are widely scattered over the area, and are particularly common on the flatter 
upland parts formed of the flow rocks of the Kerikeri Series, and round the shores of Lake Oma- 
pere where insilting has taken place. They occur wherever the drainage is poor, and are all 
shallow, except on the later basic volcanics. Not infrequently the s\\amps on the Kerikeri 
and later basic lavas contain deposits of bog iron-ore. 

Mangrove " swamps," which are correctly tidal flats on which mangrove-trees grow, 
have been mentioned in connection with the shore-line (page 29) and in the section on the 
flora of th.e subdivision (page 4). 

Springs. 

The springs of the Whangaroa Subdivision may conveniently be classified as common 
and mineral. 

Common springs — that is, springs of cold water suitable for ordinary domestic purposes 
— are of general occurrence throughout the subdivision, but are most abundant in those areas 
which are covered by volcanic rocks. None is of sufficient size to require special notice. 

Mineral springs occur chiefly in the south-east corner of the subdivision. A few less 
important ones are, however, found near the head of Whangaroa Harbour. They may be 
subdivided into so-called soda springs and sulphur springs. In no case, however, except 
Neilson's Soda Sprmg, is there more than a very slight flow — a pint or less a minute. Most 
of the mineral springs are, in fact, small surface springs through which gases escape, and which 
are sometimes warmed by escaping steam. 

(a.) Soda Springs. — On the southern edge of the Waikoura nuid-flat is a small cold spring 
having a flow of about li pints a minute.* There is some ebullition of gas, apparently carbon- 
dioxide, from the surface. The water is not unpleasant to the taste, but is rather bitter. 

Its analysis is as follows : — Grains 

per Gallon. 
Sodium and potassium chlorides . . . . . . . . 18-1 



Sodium-bicarbonate . . 
Calcium-bicarbonate . . 
Magnesium-bicarbonate 
Ferrous bicarbonate . . 
Sodium-silicate 



* On the 14th October, 1908, 



126-6 

127-5 

26-3 

2-9 

2-7 



, -aifBO apHM .. J" 'lo J, 



,'980\ s.djjna . 



2 

.J 

Ou 



.•jjOflijsX'BH 







g - 
o o 



w .a 



>— t 


C8 




te- 


U5 


P- 


g 


-d 




d) 


ffi 


•c 


cn 


-o 




(U 


a 


J3 


o 


>. 


e 


^ 


b 


5 






>< 


5 


-i; 


_N 


ca 


'C 




o 


o 


J3 


^ 


->^ 


o 


s 

E 


■«i 




:« 


13 


o 


aj 




J3 




-^ 






o 


M 




S 


^ 


o 


r^ 


JS 


SI 


c« 






J> 





o 



3 
03 



37 

This spring rises through the greensands of the Kaeo Series. Of probably more superficial 
origin are the numerous soda springs which are scattered over the mangrove swamps at the 
head of Whangaroa Harbour. These are found well out in the swamps, away from any pos- 
sible outcrops of consolidated sedimentaries, and are depositing practically no sinter. They 
are not springs in the true sense, but merely escapes of carbon-dioxide and other gases 
taking place through pools of water. The gases are probably derived from decomposition- 
processes going on in the carbonaceous mud of which these swamps are composed. 

A large spring, slightly warm (temperature, 29° C.*), occurs just beside Mr. Neil Neilson's 
house, near the Ngawha Settlement. The basin of this spring has a surface of about 15 square 
feet, and is situated on a low mound of glassy or vesicular sinter about 18 ft. in diameter. 
The flow of the spring was found to be about 4i quarts per minute.f The water is of a not 
unpleasant ta.ste, and is very clear; but floating on the surface is a scum showing a little petro- 
leum, while round the edge and on the bottom grow alg;e coated with iron-o.xide. There 
is considerable ebullition of gas. An analysis of the water is as follows : — 

Grains 
\)er Gallon. 
Sodium and potassium chlorides . . . . . . . . 2-6 

Calcium- bicarbonate .. .. .. .. .. .. 81 

Magnesium-bicarbonate . . . . . . . . 8-.S 

Ferrous bicarbonate .. .. .. .. .. .. 1-2 

Sodium-silicate .. .. .. .. .. .. lJ-6 

Free carbou-dioxide (CO2) .. .. .. .. .. 350 

(b.) Sulphur Springs.'^ — In addition to the gas-vents in the ponds mentioned in the pre- 
ceding section, spring.s from which hydrogen-sulphide and other gases escape are common 
at many places on the old Ngawha Lake basin round the Ohaeawai Hot Springs, and at various 
places on the southern and eastern flanks of Putahi Hill. Another small group of springs occurs 
on the Putahi Ridge, at the headwaters of the (Jhaputu Creek. 

The water from a group of cold sulphur-springs on the left bank of Te Pukoro Stream, 
near Mr. Neilson's house, was submitted for analysis, with the following results : — 

Grains 
per Gallon. 
Sodium and potassium chlorides . . . . ..20 

Silica .. .. .. .. .. .•^0-5 

Free carbon-dioxide (COo) .. .. .. 440 

Free sulphuric acid (H 2 S()^) .. 1-5 

Sulphuretted hydrogen (HjS) . . . . 0-8 

The hot springs of the subdivision are entirely limited to the valleys of tributaries of 
the Ngawha Stream. Those on th<' .shores of Tuwhakino Pond and the hot pools at Waite- 
tera Pond have already been mentioned. Besides these, then^ are some five small areas in 
which water warmed by escaping .steam occurs on the Tuwhakino Stream, above; the pond 
of the same name. The lowermost of these (No. 5 on detailed n\ap of mercury- workings) 
shows abundant hydrothermal and gaseous activity, and is consequently most interesting. 
On both sides of the small stream which winds across the flat (Plate XVII) hydrogen- 
sulphide and other gases bubble up violently, as individual jets in the sand, or from the .sur- 
face of the various pools. On the right side of the creek are numerous pools of warm or hot 
water, some four or five of which are actually hot-spring vents, while others are artificial 



* Temperature of air at time of observation, 18° C. 

■j- On the 5th October, 1908. 

I Cox, in his "' Xote.s on the .Mineralogy of New Zealand " (Tran.s., 1882, vol. xv, p. 362), mentions mineral 
spiingb at Ohaeawai, Auckland, ranging in temperatuie from 60° to 116° Fahr., and yielding 16-8 gr. of solid 
matter per pint. 



38 



excavations whicli have filled with water and are heated by steam. In places steam-jets 
issue from the surface of the ground without any pool. The hottest springs are in this area. 
One has a temperature of about 81° C, while another averages 62° C, and still another 
averages 48° C. The rest are much cooler, and average only about 30° C. Steam-vents 
occur with a temperature of 80° 0.* The following is the result of an analvsis of the water 
of the hottest spring :— Grains 

per Gallon. 

Sodium-chloride . . . . . . . . . . 87-0 

Potassium-chloride 

Sodium-sulphate 

Calcium-sulphate 

Magnesium-sulphate 

Sodium-bicarbonate 

Ferrous bicarbonate 

Sodium-silicate . . 

Gold 

The springs are depositing siliceous sinter containing mercuric sulphi 
details as to the composition of this sinter will be found in Chapter VI, page 92. Gas is 
escaping at many orifices in the fiat mud surface round the springs and in the surrounding 
country. Mining operations have altered considerably the original appearance of No. 5 area, 
but the flat is seemingly an old explosion-crater. 

About 12 chains higher up the creek is another depressed area (No. 4 on map), in which 
is a single warm pool from which steam and gas issue. It bears considerable hydrogen-sul- 
phide, and has a temperature of 25° C.J Numerous pools in active ebullition are found on 
the same flat, but are all cold. In the next area (No. 3) mine-workings have almost com- 
pletely altered the original surface. No true springs now occur, but the old mine-workings, and 
holes dug anywhere round about, fill with water at a temperature of from 30° C. to 55° C, the 
heat being the result of the steam issuing through the water. The following is the result 







. 12-7 






. 3-4 






. 2-4 






. 65-0 






. 1-0 






7-1 






. 0-0000058t 


uric sulph 


ide (cirmabar). Further 



of an analysis of water from one of these holes 



Grains 
per Gallon. 

29-9 
2-1 

13-3 
8-4 
3-1 
015 
0009 
0004 
0-225 



S odium- chloride 
Potassium-chloride 
Sodium-sulphate 
Calcium-sulphate 
Magnesium-sulphate . 
Hydrogen-sulphide (HoS) 
Arsenious oxide (AsjOs) 
Manganese-oxide 
Mercury 

In area No. 2 the most vigorous thermal phenomena of the subdivision are to be seen. Here 
in a space of about half an acre are a great number of springs — some hot, some warm, others 
quite cool — from nearly all of which gases are evolved. At some of these orifices the ebulli- 
tion is very violent. Steam issues in places, forming " porridge pots " of mud, which is black 
owing to the large amount of carbonaceous matter. With two exceptions, all the springs of 
this area are rich in petroleum. The spring with the highest temperature varies from 60° C. 
to 66° C, while the other warm springs range from 27-5° C. to 50° C.§ 

* The temperature of the air during these observations averaged 10° C 

f Equivalent to 0-0013 gr. per ton of water. 

t Average temperature of air at time of observations, 18° C. 

§ Average temperature of air at time of observations, 9-5° C. 



39 



The following is the result of an analysis of water from one of these springs : — 

Grains per Gallon. 
Sodium-chloride . . . . . . . . . . . . 1-5 

Sodium-sulphate i . _ 

D-0 



Potassium-sulphate j 

Ferrous sulphate 

Calcium-sulphate 

Magnesium-sulphate . . 

Silica (SiO^) 

Free sulphuric acid (H2S0^) . . 
In area No. 1 there are no true warm springs, but the 
perature of 23° C".* From this water a violent ebullition of gas is constantly taking place. 
The following is the result of an analysis of this ga's : — p ^^ . 



01 

24 
0-3 
10-2 
.. 108-0 
water filling the shaft has a tem- 



Carbon-dioxide (COj) 

Hydrogen-sulphide (HjS) 

Methane (CH J 

Air 

Nitrogen 



.All analysis of the water HUirig the shaft is given below 
Sodium-chloride 
Sodium-sulphate 



. . 87-3 

V^ery slight trace, f 

7-4 

2-3 

30 



Potassium-sulphate 

Ferrous sulphate 

Calcium-sulphate 

Magnesium-sulphate 

Silica (SiOj) 

Free sulphuric acid (HjSO^) 

Free carbon-dioxide (COj) 

Hydrogen-sulphide (HjS) 
Like area No. 5, No. 1 has been greatly altered by mining operations. 

The following analysis of mineral water from the " hot springs at the Bay of Islands "J is 
of interest owing to the presence of hydrochloric acid, a certain amount of which was ap- 
parently free. Although it is certain that this sample came from the Ohaeawai Springs, 
the e.xact location is not given. It thciefore seems possible that the spring has since become 

extinct : Grains |jer Gailou. 

Proto.\ide of iron . . . . . . . . . . 2-23 



1000 

(irains per Gallon. 

II 
20-2 

6-3 

4-1 

6-7 

3-6 

3-6 
50-9 
49-5 

11 



Lime 










5-97 


Magnesia 
Silica 










115 
3-10 


Sulphuric acid 
Hydrochloric acid . . 










13-60 
. 66-91 


Sulphuretted hydrogen 
Fixed alkalis 










. Traces. 
. 41-66 


Ammonia . . 










. Traces. 


Organic matter 










. Traces. 



134-62 

* Average temjieratire of air at time of observations, 9-5° C. t The amount of hydrogen-sulphide 

was too small to be accurately determined, being less than 0001 yjer cent. I " On Certain of the 

Mineral Waters of New Zealand," by W. Skey, Trans., 1877, vol. x, p. 425. 



40 

Further details in connection with the hot springs will be found in the chapter dealing 
with economic geology. 

Man's Influence on the Physical Features. 

The trenches and terraces which mark the sites of the old fortified villages (pas) of the 
Maoris have slightly altered the contour of many hills in the subdivision. 'J'he positions of 
the more important of these pas are indicated on the geological maps. 

During the process of " driving " timber* the erosive power of the stream employed 
is increased many times. Owing to the soft nature of many of the rocks of the Whangaroa 
Subdivision the effects of this erosion are particularly striking, and may be well seen in any 
" driving creek " which has been in use within the last ten years. During a " drive " the 
great logs act as very efiective battering-rams, tearing away the minor irregularities, and 
leaving the stream with a bed which it can fill only in flood-time, and which it cannot, under 
ordinary conditions, keep clear of debris slipping in from the sides. A stream which, left 
to itself, would occupy a mere runnel at the bottom of a densely bushed gully will, after being 
" di'iveu out," How along a trench several yards in width, and bordered by steep scoured 
banks. As time goes on, the steep banks become clothed with a dense growth of bracken, 
tutu {Coriaria ruscifolia), &c., and the stream meanders down the broad trench between 
miniature terraces of reassorted debris, which it is unable to remove without the powerful 
aid of the waters of a " tripped " dam. It is to the great loads of debris which have been 
brought down by " driving creeks " that the rapid insilting of the head of Whangaroa Har- 
bour since the middle of the nineteenth century is mainly due. 



* See Chapter I, p. 16. 



PLATE X. 

Kowbairoa. JUa .1" Haystack. " 



Peach Stephenson 
Island. Island. 




liOWKii Paut ok Wii.\.N(;.\ho.\ ILvkhulu i-ku.m tiik Si.orios of Si. 1\\li.'s. 



Waitaruke 
Settlciiit-iit. 



Ferguson 
Tai'atiiia. roiiit. 





Head ok Whang ahoa Hahbouu khom thk Slopes of St. Paul's. 
Bulletin. No. 8.] ^Face f. 1,0. 



41 



CHAPTER IV. 



THE STRATIFIED ROCKS. 



The Waipapa Series 
(a.) Introdurtory 
(6.) General Distribution 
(r. ) Structure 
[d.) Petrology 

Argillites . . 
Grauwackes 
Quartzites . . 
Friction Breccias 
Schistose Rocks 
Marble 
(e. ) Mineralisation 
(/.) ('orrelation and Age 
The Kaeo Series 
(a.) Introductory 
(6.) General Distribution 
(c. ) Structure, Distribution, and Inter- 
relationships of the Different 
Members of the .Series 
(Conglomerates 
Tuffs 

(^ncretionary Shales, Clay- 
stones, Sandstones, and Shaly 
Impure Limestones 
Massive Limestones . . 
Greensands and Claystones 
Calcareous Sandstones 
(d.) Petrology 

Conglomerates 



Pag«- 



41 


The Kaeo Series — continued. 




41 


(rf.) Petrology — continued. 




41 


Tuffs 


.")() 


42 


Concretionary Shales, Clay- 




43 


stones, Sandstones, and Shaly 




43 


Impure Limestones 


51 


44 


Massive Limestones. . 


53 


44 


Greensands 


54 


44 


Calcareous Sandstones 


55 


44 


(f.) Palseontology 


55 


45 


Fossils of the Concretionary 




45 


Shales and Sandstones 


56 


45 


Fossils of the Greensands 


57 


46 


(/.) Correlation and Age 


58 


46 


.NY'iiwha Lake Beds 


58 


46 


High-level Uiver Terraces 


59 




lieccnt Dej)osits 


60 




(a.) Hot and Cold Spring Dejwsits . . 
(b.) Fluviatile lJe])03its 


60 


47 


61 


47 


(1.) .Alluvial Flats .. 


61 


48 


(2.) Swamps 


62 




(c.) l..acustrine Deposits 


62 




((/.) Fluvio-mariue and .Marine De- 




48 


posits 


62 


48 


(1.) Estuarine Deposits (Tidal 




49 


Flats) 


62 


49 


(2.) Sand and other Marine 




49 


Detritus 


62 


49 







The Waipapa Series, 
(o.) introductory. 
The oldest stratified rocks found in the Whangaroa Subdivision are a series of argillites, 
grauwackes, cherts, (|uartzites, and crystalline limestones. With these are associated 
contemporaneous igneous rocks, which will he described in Chapter V. The rocks of this 
series have been subjected to considerable folding, faulting, and brecciation, and in a few 
localities have been rendered schistose. 

No palicontological evidence of the age of these strata is available, and the writers have 
therefore applied to the series the now name of Waipapa, whicli has no age-signification. 



(6.) (JKNKKAL DISTRIBUTION. 

The Waipapa Series is exposed both inland, in the area which is drained by the Waipapa 
River and its tributaries, and also along the greater part of the sea-coast of the subdivision. 
As indicated in the geological maps, these areas now appear quite separate. It seems pro- 
bable, however, that the lava-shrouded country along the eastern boundary is underlain bv 
Waipapa rocks — i.e., that the two areas were visibly connected until Tertiary times. 

The inland exposure of Waipapa rocks covers an area of about 48J square miles. It 
extends from the headwaters of the Kerikeri River in the east to the western boundary of the 
subdivision, and from the lower part of the Pirau and Waipapa rivers in the south to the upper 
waters of the Pupuke River in the north. An isolated patch of Waipapa rocks occurs in 
the upper waters of the Waiarewau Stream near Pimgaere. 



42 

The coastal expoaure covers in all an area of about 18J square miles. It is divided into 
two portions by the Miocene breccias of the Wairakau Series in the neighbourhood of Whanga- 
roa Heads. The eastern portion extends along the coast from the eastern boundarv of the 
subdi\nsion to the eastern point of Tauranga Bay, and inland for about two miles near the 
head of Wainui Creek, but the exposure narrows towards Tauranga Bay. It also includes 
Stephenson Island and the small islets east of Whangaroa Heads, with the exception of Flat 
Island and Motuekaiti. 

Save for insignificant exposures, the western portion of the coastal area of Waipapa rocks 
is first met along the coast about half a mile north of Taupo Bay. From this point to Tupo 
Baj-, both inland and along the coast, the most abundant rocks are igneous, but the more 
ancient Waipapa rocks are occasionally seen. From the western end of Tupo Bay to the 
boundarv of the subdivision the proportion of intrusives is less, and the Waipapa sedimentaries 
are predominant, but do not outcrop inland from this part of the coast-line for more than 
half a mile. 

(C.) STRUCTURE. 

The Waipapa Series is excessively jointed, fractured, and faulted. The rocks are nearlv 
always traversed by several systems of joints, which cause them to split up into small blocks. 
Small dislocations are of common occurrence along these joint-planes. Minor faults are 
common, especially on the coast between Taupo and Frear bays. Only very occasionally 
does anv approach to schistosity appear. A schistose structure is, however, apparent in the 
rocks for some distance between Camp Bay and Taupo Bay. As a result of the excessive 
jointing and minor faulting of the Waipapa rocks it is almost always difficidt, and sometimes 
impossible, to distinguish the original planes of stratification. 

In the iuland area the strata appear to be arranged in an anticlinorium, the general trend 
of which is E.N.E. and W.S.W. In the coastal area the strata are also arranged in an anti- 
clinorium, which has a general W.N.W. and E.S.E. direction. The anticlinorium in which the 
inland portion of the series is arranged is simpler than the coastal one. In the latter case 
several pronounced synclines occur, but in the inland area the synclines are of ver\' minor 
importance, and soon die out if followed longitudinally. As a result, a much greater thickness 
of strata is exposed in the practically singly folded inland exposure than in the repeatedly 
folded coastal belt. 

Although the strikes generally conform to the trend of the principal folds, there are nianv 
notAble exceptions. The dips are usually high, ranging from 30° to verticality. 

It will thus be seen that the Waipapa rocks in the two areas show no community in general 
disposition. The axes of the two aiiticlinoria, in fact, form a V. It is possible that if the 
obscured country near tlie eastern boundary of the subdivision could be laid bare, the two axes 
would be found to swing gradually into line, otherwise wf must suppose that there is some 
ureat dislocation at the jiuiction of the two arms of the \'. 

A glance at the index map at the beginning of this report will show that the general trend 
of northern New Zealand is N.N.W. and S.S.E. Kocks which have been considered of the 
same age as the Waipapa Series are found, along the east coast, in the Bay of Islands, in the 
neighbourhood of Mangonui, near Hohoura, and at the North Cape,* but little information 
is available as to their predominant strike. Marshally considers that there is " a north or 
north-north-east strike "" in the Bay of Islands, and that " the same direction appeared to be 
represented in the hills between Mangonui and the Oruru Valley, and in the shales that are 
occasionally displaved in the range extending from Reef Point to Raetea.'" 

Although general deductions cannot be drawn from the very limited area under present 
consideration, it is e\'ident that, as Marshall concluded from the examination of presumably 

* Hector, " Progress Report," Rep. G.S. during 1890-1, No. 21, 1892, pp. Ixxx and Ixxxi. 
t " Geology of Centre and North of North Island," Trans., vol. xl, 1907, p. 81. 



PLATE XI. 






Micro-photographs of Waipapa and Kaeo Rocks. 



1. Quartzite, Waipapa Series, head of Kerikeri River. 

2. Schistose rock, Waipapa Series, between Taupo and Camp bays. 

3 and 4. Granitic pebbles, basal conglomerate of Kaeo Series, Pa Island. 

All magnified about 30 diameters. 
Micro-photo, bi/ Dr. P. Marshall.'] 
Bulletin No. 8.1 



Nicols crossed. 



[Face f. p. 



43 

coeval rocks exposed over a wider area, the arrangement of the Waipapa rocks shows little 
connection with the general trend of the North Auckland Peninsula. 

(d.) PETROLOGY. 

Generally speaking, the non-volcanic Waipapa rocks of the coastal area are rapidly alter- 
nating beds (sometimes only a few inches thick) of argillite and impure chert, with somewhat 
uncommon quartzite. In a broad way, the rocks are most arenaceous and silicitied to the 
east and south of Wainui Bay. On the other hand, the sedimentary rocks of the inland 
area are finer in grain, and show only occasional variations from fine-grained argillites to 
grauwackes. 

Argillites. — The argillites are fine-grained rocks, generally dull-green in colour, but showing 
in places sudden variations — ^within a distance of a few chains — to red, green, and black. 
No minerals are visible to the naked eye except secondary pyrite and silica, with which the 
rocks in question are very frequently impregnated, and which sometimes form small non- 
persistent veins. Beneath the microscope it becomes apparent that the argillites are made 
up mainly of very fine grains of feebly doubly refracting minerals, the recognisable members 
of which appear to be chiefly feldspars. It is probable that both chlorite and quartz are also 
present, but they are not identifiable. Microscopic seams of chalcedonic quartz and crystals of 
pyrite are conunon. 

Argillites are the characteristic rocks of the Waipapa Series, and arc found in all parts 
of the areas in which these rocks are e.xpo.sed. 

Further remarks on the mineralisation of those and the other rocks of the Wai])apa Series 
will be found in the next section (page 45) and in Chapter VI, pages 93, 94, 95. 

The following are analyses of argillites — (1), from the head of Paingahuru Creek ; (2), from 
near the base of Omiru Peninsula. Although silicified, No. 1 was considerably decomposed, 
apparently by the removal of secondarj' pyrite. The porosity of the rock probably explains 
the high percentage of water and organic matter. 

Silica (SiOj) . . 
Alumina (AljOg) 
Ferric oxide (Fe^Og) 
Lime (CaO) 
Magnesia (MgO) 
("arbonic anhydride (C()^) 
Water and organic matter 
.\lkalis and undetermined 

lOOOO lOOUO 

A white, rather soft and uiictuous rock occurring in a narrow seam in the Wainui Creek, 
about three-quarters of a mile from the sea, was analysed, with the following result : — 
Silica (SiOj) . . . . 65-63 

Alumina (AUOg) . . .. .. . . 18-22 

Ferric oxide (FcjO,) 3-20 

Lime (CaO) .. 1-21 

Magnesia (MgO) . . . . 0-80 

Carbonic anhydride (CO 2) .. .. .. Nil. 

Water and organic matter . . 6-14 

Alkalis and undetermined . . . . . . 4-80 

10000 



No. 1. 


No. 2. 


73-75 


62-80 


3-46 


11-53 


1-04 


11-29 


0-45 


4-97 


3-60 


1-60 


Nil. 


Nil. 


14-50 


3-92 


3-20 


3-89 



44 



Grauwackes. — The grauwackes are usually dark-green in colour, and are very frequently 
silicified. In a general inspection they resemble the argillites, but are coarser in grain. Quartz 
and pyrite are practically the only minerals recognisable in a hand-specimen. 

Beneath the microscope the constituent grains are seen to consist of quartz and feldspar 
in variable proportions. The feldspars are much altered, but are apparently mainly plagio- 
clase. Granules of pyrite are of almost universal occurrence. 

The grauwackes, though less abundant than the argillites, are of general distribution in all 
horizons of the Waipapa Series. 

Quartzites. — The quartzites are white compact rocks, in which the component grains 
camiot be identified with the naked eye. 

Microscopic examination of the quartzites shows that, with the exception of a few rare 
fragments of decomposed feldspar, they are made up chiefly of quartz granules of generally 
small size, which show undulatory extinction. There is also a considerable amount of very 
fine clastic material. The secondary silica by which the grains are cemented together is in 
crystallographic continuity with the grains. Under crossed nicols the rock, therefore, has 
the appearance of an irregular mozaic. (Plate XI, No. 1.) 

The following is an analysis of quartzite from Whakarara Hill : — 



Silica (SiO 2) 


94-35 


Alumina (Al 2 O3) .. 


0-60 


Iron-oxides (FeO and FcjOa) 


2-40 


Lime (CaO) 


1-01 


Magnesia (MgO) 


0-40 


Carbonic anhydride (CO2) .. 


0-85 


Moisture and organic matter 


0-39 



10000 

The prominent hill of Whakarara, with the siirrounding country, covering an area of about 
three-quarters of a square mile within the subdivision, is composed of quartzite. Outcrops 
of a similar rock occur at Mr. Copeland's house near the upper waters of the Waiarewau 
Stream, near the headwaters of the Manginangina branch of the Kerikeri River, and near 
Puketi. 

Friction Breccias.- — On the coast at Matanohinohi the Waipapa rocks have been pene- 
trated by dvkes of semi-basic igneous rocks, now considerably altered, but apparently ranging 
from andesites to diorites. Later, this complex of igneous and sedimentary rocks has 
been intensely fractured, and injected by later dykes, also of a semi-basic nature. The zone 
of brecciation is about 5 chains wide, passing on the south-east into the Waipapa rocks with 
their basic intrusives, and on the north-west into the main mass of the later intrusive rock. 
There are smaller occurrences of friction breccia on the west coast of Tupo Bay ami in the 
Mangakino about half a mile above its junction with the Whakateterekia. 

Schistose Rocks. — In hand-specimens the schistose rocks show a sheared structure, and are 
generally of a dark-green colour. Beneath the microscope they are found to consist mainly 
of an aggregate of zoisite grains, in which are embedded numerous granules of quartz and 
minute laths, many of which are sillimanite, and the rest unidentifiable. There is a good 
deal of chlorite arranged in wavy streaks, and, in the less metamorphosed parts, altered 
plagioclase-feldspars can be recognised. Pyrite is fairly abundant. (Plate XI, No. 2.) 

Schistose rocks are found on the coast-line between Taupo Bay and Matanohinohi. 
Judging from the characters of the least metamorphosed parts, it seems probable that these 
rocks are mainly intrusives into the Waipapa Series, and have been rendered schistose by sub- 
sequent shearing- movements. 



45 

Marble. — A white or greyish- white compact crystalline limestone occurs, associated 
with the volcanic rocks of the Waipapa Series, along the coast-line between Tauranga and 
Kairauwaru bays. Several beds outcrop, never, apparently, more than 6 ft. in thickness, 
and sometimes much less. By movement subsecjuent to the deposition of the Waipapa rocks, 
the beds of marble have been much brecciated, and mixed with the associated volcanic and 
sedimentary rocks. The development of crystalline structure in this rock is mainly, no doubt, 
due to regional metamorphism, since the igneous rocks, near which it occurs, are surface flows 
and breccias which would have had little or no metamorphic effect. 
An analysis of this n\arl)lo yields the following results :— 

Silica (SiOJ . . . . . . . . . . . . OU") 

Alumina (AljOg) . . . . 0-55 

Ferric o.xide (Fe^Og) .. 0-70 

Lime (C'aO) . . 54-00 

Magnesia (MgO) 0-50 

CarVmnic anhydride (COa) . . . . . . . . 42-43 

Water and organic matter . . 0-72 

Alkalis and undetermined 015 



100*00 



An ini])ure crystalline limestone appears in the gorges of tin; Waipapa River about two 
miles and a half above the jun(;tion with the; Whakanekerieke. 

(e.) MINERALISATION. 

As a rule, the rocks of the Waipapa Series do not, except for silicification, exhibit any 
great amount of alteration. Irregular seams and stringers o\ (juartz are very common, but 
definite veins are rare. A large number of quartz samples from Waipapa rocks in many 
localities proved quite barren on l)eing assayed. Impregnation with manganese-ore is a 
common phiiiionu'non. more especially in the eastern portion of the inland area. Small veins 
near the ba.se of Omirn I'eninsula, containing ()2- 40 per cent, of ferric oxide (Ke^O.,), and 
also 002 jxM' cent, of manjianous oxidf. yield no liohi or silver. (.Quartz strinjjers are 
abundant near Kairauwaru Hay, but are (|uite barren. 

On the northern side of Krear Hay. small dark stringers, ramifying throu>,'h the VVaij)ap;i 
argillites in close proximity to a dyke of old igneous rock, were found to (-oiitain a small 
amount (0-55 per cent.) of manganous oxide. 

On the coast near the western boundary of the subdivision, mineralisation is more pr(»- 
nounced than in the places already mentioned. Further description of this neighbour- 
hood will be found in Chapter VI, page 93. 

Calcite veinlets ar«' very fre(|uent near, and in tin' zones of, contiMnporant'ous igneous 
rocks. S('\('ral of these veinlets were examined for a variety of nicfals, t)ut were found to 
be (piite barren. 

(/.) CORRELATION AND AGE. 

No fossils having as yet been found in the rocks of the Waipapa Seriets. nothing mon; 
definite can be said of its age than that it unconforraably underlies rocks containing fossils 
of a Cretaceous aspect, and is therefore probably Palfeozoic or Earlv Mesozoic. 

The Waipapa rocks form the basement series throughout the subdivision. Direct uncon- 
formity between them and younger rocks is seen in various places. The\' are unconform- 
ably overlain by the Kaeo Series at Pa Island, at the west end of Taupo Hay, at several places 
in Whangaroa Harbour, in the upper waters of the Whakateterekia, Pupuke, Tangitu, Tame 
Pureha, and Kiti Tawa streams, and in the middle waters of the Mangapukahukahu and Pirau 



46 

cre(!l<.s. The Waiiakau breccias of Miocene age are seen uncouforniably overlying Waipapa 
rocks only near False Head, hut in Mahinepua, Wahinepua, and Tauranga creeks, outcrops 
of the two series are found very near together, and the unconformable relations of the two 
series are undoubted. They are unconforinabiy overlain by Kerikeri dolerites on Motue- 
kaiti Island. 

Hector* correlates the rocks of the Waipapa Series with those found at North Cape, Ho- 
hoiu-a, and Mangonui, in the Cape Brett - Puhipuhi area, and at Tararu Point, near Thames, 
and considers them to be Palaeozoic. McKayf draws attention to the widespread distribution 
in New Zealand of " igneous rocks of a basic type, consisting of vesicular lavas and tufis into 
which much lime has been infiltrated, associated with Lower Mesozoic rocks," and considers 
that the WaipHj)a rocks should therefore be classified as Triassic or Jurassic. The rocks at 
Tararu Point, which Hector considers the equivalents of the Waipapa Series, will, in a bulletin 
on the Thames Subdivision which is shortly to be published, be most probably assigned to the 
Tokatea Hill Series of the Coromandel Subdivision, J which is of pre-Jurassic age. 



The Kaeo Series. 

(a.) INTRODUCTORY. 

The Kaeo Series comprises a succession of conglomerates, tuffs, greensands, claystones, 
sandstones, and limestones, which is extensively developed in the valley of the Kaeo River — 
whence the name temporarily applied to it. The series covers 138^ square miles — the largest 
superficial area occupied by any series in the subdivision. 

(6.) GENERAL DISTRIBUTION. 

In addition to several smaller patches, the Kaeo Series occurs in two main areas separated 
by the inland block of Waipapa rocks and by the flows of Kerikeri volcanics. Beneath the 
latter they are, however, probably continuous. Most of these exposures, both great and 
small, appear at the surface owing to the removal by denudation of the shrouding volcanic 
rocks of later date. The more elevated portions, however — such as parts of the area drained 
by the Mangatawai and Ngawha streams, and parts of the high lands to the south of the 
Utakura River and between the Pupuke River and the headwaters of the Takakuri — were 
probably too high to be covered by the lava-flows and breccias, and, as already mentioned 
(Chapter III, page 27), represent monadnocks of Kaeo rocks on the old peneplain. 

The largest single area covered by rocks of the Kaeo Series is that lying in the northern 
half of the Kaeo Survey District, and extending almost across the subdivision. Thence the 
Kaeo rocks extend northward into the Whangaroa Survey District, as far as the north shore 
of Okamoko Bay, in a narrowing band bordered by the Wairakau volcanics and by the rocks 
of the Waipapa Series. This area of Kaeo rocks covers 69 J square miles — i.e., just one-half 
of the total area of Kaeo rocks in the subdivision. 

In the southern part of the Omapere Survey District a continuous exposure of Kaeo 
rocks, covering about fifty square miles, extends westward to the boundary of the subdivision 
and northward as far as the Whakanekeneke River, being bounded by the Kerikeri and the 
later basic lava-flows along an exceedingly sinuous line on the east. 

The boundary between the Kaeo Series and the younger Wairakau and Kerikeri rocks 
is very irregular, exposures of Kaeo rocks extending in long narrow strips up the valleys of 



* " Progres.s Re])oits," Rep. G.S. during 1890-1, No. 21, 1892, p. Ixxx, and Rep. G.S. during 1892-3, 
No. 22, 1894, p. xxii. 

f '■ Geology of Hokianga and Mongonui Counties, Northern Auckland," Rep. G.S. during 1892-3, No. 22, 
1894, p. 88. 

J Bull. No. 4 (New Series), N.Z.G.S., 1907, p. 41. 



47 

all the more important streams, whilst the adjoining uplands are made up of Wairakau or 
Kerikeri rocks. Many isolated patches of Kaeo rocks appear in the more deeply denuded 
areas, more particularly in the eastern part of the subdivision, the most important occupy- 
ing that part of the Waitangi Valley which lies within the subdivision. 

(C.) STRUCTURK, DISTRIBUTION, AND INTKR-RKLATIONSHIPS OF THE DIFFERENT MEMBERS OF 

THE SERIES. 

The rocks of the Kaeo Series have not been subjected to widespread folding. They have, 
however, undergone a considerable amount of faulting and disj)lac(Mnent, especially along the 
Pirau, Waitangi, and possibly the Whangaroa fault-lines, and to a minor extent in Tiane Creek, 
and in many other places. While, therefore, as a general rule, the dij)s are moderate, seldom 
exceeding 30° or 40°, an examination of the geological maps will show that the strikes are so 
variable in orientation that it is difficult to pronounce any direction as being that of the pre- 
valent strike. In the northern area, however, one bed — a calcareous sandstone — is sufficiently 
distinctive to be traced for nearly five miles in a north-and-south direction. It may there- 
fore be concluded that, in the northern area of Kaeo rocks, the strata are arranged meridionally. 
In the southern area, it is probable that upfaulting of the Waipapa rocks along the Pirau fault 
has taken place, and has con.siderably altered the original disposition of the Kaeo beds. 
Judging from the outcrops of a bed of limestone — the only stratum of sufficiently definite 
petrological character to render it recognisable over an extended area — ^the strike of the Kaeo 
Series in the southern area is E.N.E. and W.S.W. 

Generally, the rocks of this series are only sliglitl\- indurated. (Jnc notable exception 
is found in the zone of silicified and somewhat mineralised country which runs from near the 
headwaters of Sievers Creek northwards through the lower courses of the Waikare, Huia, 
Pahuhu, and Waikoura creeks, and is last seen on the shores of the Whangaroa Harliour, 
near the mouth of St. Paul's Creek. Silicificatiou is not, however, equally noticeable at all 
points in this zone, being, for example, much more pronounced in the Waikoura and Pahuhu 
creeks than in the Waikare and Huia. 

Owing to the erratic nature of the dips and strikes of the Kaeo rocks, and to the general 
absence of recognisable characteristics, it has not been possible to arrive at more than v(^rv 
general conclusions as to the order of superposition of the rocks. However, the succession 
from below upwards appears to be : — 

1. Conglomerates. 

2. TufEs. 

3. Concretionary shales, claystones, sandstones, and shalv imjjure limestones. 

4. Massive limestones. 

5. Oreensands and claystones. 

6. Calcareous sandstones. 

In no part of the subdivision has the complete; se(|uence l)ecn found, and, since the above- 
classification is not based on palfeontological characters, it must be regarded as tentative. 

C'o«r//ow'p;«/c.s-. -Conglomerates separating the Kaeo rf)cks from the older Waipapa Serii-s 
are found — (a) near Pa Island, at the north-west end of Taupo Bay, and along the <!astcrii 
shore of Whangaroa Harbour from the mouth of Waipahihi Creek nearly to Kaheka Point ; 
(b) on the western shore of \\'hangaroa Harbour at Cape Horn, in Rukuwai and Sherman 
creeks and their branches, and near the headwaters of the Whakateterekia and Kiti Tawa 
streams ; and (c) on the Mangapukahukahu Creek. Grits and fine conglomerates also occur 
in Oteroa Creek at the most northerlv portion of its course, and near the head of Billings Creek, 
where they probably indicate unconformities with extensions of the Waipapa rocks hidden 
under the Kerikeri lava-flows. 



48 

It will be shown, in describing the petrology of the Kaeo Series, that the conglomerates 
found at the localities grouped under (a) difler from the rest in containing abundant frag- 
ments of granitic rocks, and that the conglomerates found round Whangaroa Harbour and 
on the sea-coast, are apparently conformably succeeded by tufaceous rocks which are found 
elsewhere in the subdivision only in Papakanui and Sievers creeks, and are different from 
anv other members of the Kaeo Series. 

The fact that the granitic conglomerates found at the localities eimmerated under (a) must 
have been derived in part from a granitic land, while the peb))les of the conglomerates found 
in the places in [b) and (o) probably came from a non-granitic land, might be interpreted 
as indicating that the granitic conglomerates belong to a series distinct both from the Waipapa 
and Kaeo series. A serious objection to the above interpretation in the occurrence of the tuffs, 
the distribution of which is detailed below, overlying both granitic and non-granitic 
conglomerates, is, however, quite disposed of if the view that tlie tuffs belong to the Wai- 
rakau Series proves to be correct (see page 51). In sjjite of careful search in all likely places, 
further and more definite evidence on this (juestion was not obtained. The writers have 
therefore tentatively correlated the conglomerates and tuffs occurring on the coast-line with 
the rather different basal strata of the Kaeo Series as developed elsewhere. 

Tuffs. — The tuffs — as to the correct position of which there is much doubt (see page 51) 
— are exposed on both shores of Whangaroa Harbour. On the west side they extend from 
Cape Horn to the neighbourhood of St. Peter's Hill, and are also found in the various small 
creeks which flow into this jmrt of the harbour. On the east side of the harbour they are 
found along the shore-line from the mouth of St. Paul's Creek to Kaheka Point, and at intervals 
as far as Jones Island. They also occur in Papakanui Creek and in Sievers Creek, above 
the Domain Road Bridge. 

Concretionary Shales, Claystones, Sandstones, and Shaly Impure Limestones. — The con- 
cretionary shales, claystones, and sandstones have their chief development in the lower half 
of the Pupuke River, in Waihapa Creek, at the head of Whangaroa Harbour, in the neigh- 
bourhood of the Settlement of Sales, and near Mr. Nelder's house, on Waitapu Bay. 

The impure limestones belonging to this group of the Kaeo Series are generally in close 
connection with the shales and sandstones. They have a wide distribution, though they 
are seldom very extensively developed in the subdivision. On the Kaeo-Mangonui Road, 
at the turn-off to Whangaroa, and on the low ridge which the Kaeo-Mangonui Road crosses 
about half a mile further west, a soft marly limestone is seen to underlie the greensands — 
to be later described — and is probably the equivalent of the concretionary shales already 
described. A very compact calcareous sandstone, fomid on a southerly extension of the same 
low ridge on the left bank of the Kaeo. opposite Mr. J. Hare's house, is probably of the same 
horizon, though in chemical composition it approximates rather to the calcareous sandstones 
described below. 

Massive Limestones. — The massive limestones appear only in the Omapere Survey Dis- 
trict, where a broken band seems to follow a north-west and south-east course. They occur 
in the middle waters of the Pirau Creek, in close proximity to the more ancient Waipapa 
rocks ; thence they strike south-east, being next found in the Waikaraka and its tributaries — 
the Arotoro and Poro-te-Koihamo streams. In this neighbourhood the limestones have their 
most extensive development. They are again found in the Waitangi and its tributaries — 
the Awahei and Waikuku creeks. Isolated outcrops of arenaceous limestone appear in the 
Waiharakeke and Waihoanga creeks about 15 chains above their respective junctions with 
the Utakura River, and at the head of Te Kara Creek. The prevalent rock in the basin of 
the Mangataraire* is a calcareous sandstone. 



* In Omapere Survey District. 



49 

The massive limestones, especially those found in the Waitangi and its tributaries, are 
much interbedded with greensands and claystones. 

Since the massive limestones appear to be quite separated from the shaly limestones in 
the Kaeo and ^\^langa^oa survey districts by the ridge of Waipapa rocks, and since the two 
limestones differ markedly in petrological characteristics and to some extent in chemical 
composition, any attempt to correlate them would, in the absence of palpeontological evi- 
dence, be somewhat unwarranted. It is evident, however, that, although underlain by a 
considerable thickness of greensand and claystone, the massive limestones in the Omapere 
Survey District underlie the main mass of the greensands. They therefore approximate in 
horizon to the shaly limestones of the northern part of the subdivision. 

Greensands and Claystones. — Greensands and claystones are the most extensively de- 
veloped rocks of the Kaeo Series, being found in every portion of the subdivision where the 
series is exposed, and, although given a definite position in the tentative classification adopted 
in this bulletin, they probably occur at several horizons in the series. Descriptions of the 
fossils found in the concretionary shales and sandstones, and in the green.sands, will be found 
in another section of this chapter. From these descriptions it appears that, whereas the 
lower beds of the concretionary shales and sandstones contain fossils of a Mesozoic aspect 
only, the fossils of the greensands are apparently Tertiary. The existence of a pal.fonto- 
logical unconformity renders a stratigraphical break also probable. Careful search for such 
an unconformity, however, proved fruitless, except at the head of Okahunga Creek and in 
Rotomanoao Creek, about a (juarter of a mile below the cutting through which it receives 
the waters of Parirengarenga Creek,* where the blue slickensided shales are separated by a 
conglomerate from overlying greensands, which are here non-fossiliferous, and cannot there- 
fore be correlated with the fossiliferous greensands found near Kaeo. The conglomerate, 
moreover, appears to be local, and not to mark any important break in deposition. How- 
ever, although the unconformable relationships of these two members of the series — the con- 
cretionary shales and sandstones and the greensands — have not been proved, it is also true 
that nowhere has an undoubtedly unbroken stratigraphical succession been found between 
the fossiliferous greensands and the fossiliferous concretionary' shales and sandstones. The 
stratigraphical evidence is therefore of a rather indecisive character, and it is quite probable 
that more extended observations will justify the division on stratigraphical grounds of the 
Kaeo rocks into two distinct series of Late Mesozoic and Early Tertiary age respectively — 
a division which is certainly warranted by the paheontological evidence. 

Further remarks on this matter, whieh has some bearing on the vexed question of the 
Cretaceo-Tertiary System of the former Geological Survey, will be found in the section on 
correlation and age (page 58). 

Calcareous Sandstones. — A nearly continuous band of calcareous sandstone runs from the 
Kaeo River, above Mr. Sievers's house northwards, as far as the Towai Stream. Similar rock is 
also found to a small extent in the middle waters of Inuniia Creek, forming, perhaps, a southerly 
extension of this band. 

From its field relationships, which are especially clearly seen on the ridge between the 
Waitapu and Towai creeks, it -seems probable that this band of calcareous sandstone over- 
lies the greater part of the greensands occurring in this part of the subdivision, and therefore 
occupies one of the uppermost horizons of the Kaeo Series. 

{d.) PETROLOGY. 

Conglomerates. — The petrological character of the constituent pebbles varies from place 
to place. Three general types, can, how^ever, be distinguished. The conglomerates from 



* See Chapter 1, p. l(i, 
4 — Whangaroa. 



50 

the localities grouped together under (a) in the preceding section are characterized by the 
occurrence of granophyre pebbles up to 2 in. in diameter embedded in a nmch finer arenaceous 
matrix. The conglomerates under (&) are usually made up of very small and thoroughly 
water-worn fragments of argillites and grauwackes, with little or none of the fine sandy 
material which occurs in (a). The conglomerate found in the Mangapukahukahu is chiefly 
distinguishable from (&) by the great abundance of comnunuted shell-fragments — almost 
abundant enough to constitute the rock a gritty limestone. 

(a.) The granitic pebbles from the conglomerate at Pa Island, Taupo Bay, and the eastern 
shore of Whangaroa Harbour appear on fresh fractured surfaces as white, or occasionally 
pinkish, holo-crystalline rocks, made up mainly of feldspar and quartz, but containing a few 
scattered crystals of ferro-magnesian minerals. Microscope sections show that the predominant 
type is a crystalline granular aggregate of orthoclase, with a variable but minor quantity of 
quartz and acid plagioclase and a few small crystals of hornblende, now almost entirely altered 
to bright-green chlorite. The feldspars usually show considerable kaolinisation. Micro- 
graphic intergrowths of quartz and feldspar are common, most of the quartz being in this 
habit and but little in separate grains. (Plate XI, No. 3.) 

Another less abundant type is a finely granular crystalline aggregate of quartz, orthoclase, 
and acid plagioclase, with a little hornblende converted almost entirely into bright-green 
chlorite. In this type also, however, micrographic intergrowths occasionally occur. (Plate XI, 
No. 4.) 

Granitic rocks have never been found in situ in the North Island of New Zealand nor in 
outlying islands. Boulders have, however, been reported from a stream about fifteen miles 
east of Kawhia Harbour by Park.* 

Both granites and granophyresf have been obtained from a conglomerate which outcrops 
on the east shore of Palliser Bay, near Wellington, and belongs to Hector's Maitai Series. 
Granitic boulders from a Triassic conglomerate near Nelson occasionally show a granophyric 
structure, J but fragments of porphyrite, which seem to be abundant in the Nelson conglome- 
rate, have not so far been found in the Whangaroa Subdivision. 

The micro-petrology of granitic boulders from the Kermadecs — a group of small islands 
about six himdred miles north-east of New Zealand — ^has been detailed by Thomas,§ who 
notes their granulitic structure. Granite also occurs abundantly in Fiji.H 

(&.) In the other conglomerates found at the base of the Kaeo Series granitic pebbles 
have not been found. The most abundant fragments are of argillites, the equivalents of 
which may be fomid in the Waipapa Series. Pebbles of a siliceous argillite, owing to their 
more resistant character, are the most abundant. 

Tuffs. — Microscopically the tuffs are fine-grained, apparently structureless, rocks, which 
when fresh are dark-green in colour. 

Under the microscope the authigenous constituents of the rock are found to consist chiefly 
of clear angular feldspars, only a few showing signs of twinning. With them some fragments 
of augite crystals and a few granules, apparently of quartz, also occur. The groundmass is 
exceedingly fine-grained, and cannot be differentiated under the microscope. There are 
few, if any, signs of sorting of the particles by water. The rock apparently owes its green 
colour to chloritic substances formed by the decomposition of ferro-magnesian minerals. 
(Plate XIII, No. 1.) 



* " On the Occurrence of Granite and Gneissic Rocks in the King-country," T-aus., vol. xxv, 1892, p. 353. 
•)• Sollas, " Rocks of Cape Colville Peninsula," vol. ii, 1906, p. 182, &c. 

i Cf. Marshall, " Boulders in Triassic Conglomerate, Nelson," Trans., vol. xxxvi, 1903, p. 468. 
§ " Notes on the Rocks of the Kermadec Islands," Trans., vol. xx, 1887, p. 311. 

II Woolnough : "The Continental Origin of Fiji," Proc. Linn. See. N.S.W., 1903, xxviii, p. 457; and 
" A Contribution to the Geology of Viti Levn, Fiji," ib. 1907, xxxii, p. 431. 



51 



17 04 


1-20 


409 


010 


3-64 


2-61 


3-67 


2-37 


0-93 


Nil. 


4-65 



Associated with the tuff in St. Paul's Creek and on the shore of the harbour near 
Mr. Nelder's is a very carbonaceous sandstone. A similar sandstone is found occupying the 
lowest position iti the series as exposed in Oika and Waitetoki creeks. 

The following is an analysis of a typical specimen of this tuff from a road-cutting near 
Whangaroa Township : — 

Silica (SiO,) . . . . . . . . 59-70 

Alumina (AljOg) 

Ferric oxide (FejOg) 

Ferrous oxide (FeO) 

Manganous oxide (MnO) 

Lime (CaO) 

Magnesia (MgO) 

Potash (KjO) 

Soda (Na.O) 

Titanium-dioxide (TiO^,) 

Carbonic anhydride (CO,) 

Water and organic matter 

10000 
If the above analysis be compared with that of an average sample from the breccia on 
the summit of St. Paul's (page 68), it will be seen that there is a very close resemblance. 
It must be remembered, however, that those analyses both indicate a very conmion type of 
rock, and offer no marked peculiarities which would be of great value for comparative purposes. 
There is, on the other hand, as pointed out to the writers by Professor Marshall, a strong proba- 
bilitv that these tuffs belong to the base of the Wairakau Series (see Chapter V, page 65) — i.e., 
are unconformably younger than the Kaeo rocks with which they are associated in this report. 
From a consideration of the field evidence, too lengthy to be detailed here, the writers are 
inclined to favour the present classification, but they must admit that there is strong evidence 
in favour of Professor Marshall's view. 

The zone of silicified country — the extent of which has already been defined — probably 
coincides in a large degree with the distribution of these tiifaccous rocks. 

A black depo.sit is found on joint faces in the silicified tufaceous rock at the mouth of a 
small tributary of Shepherd Creek, itself an affluent of the lower Kaeo River. This yielded 
2-46 per cent, of manganese-dioxide and 209 per cent, of manganous oxide, the mineral being 
probably in the form of manganite. 

In the silicified zone, quartz veins occur, which will be described in Chapter VI (page 93). 
Concretionary Shales, Claystones, Sandstones, and Shaly Impure Limestones. — The three 
first-mentioned species of rock consist of soft, incoherent, often rapidly alternating shales, 
claystones, and sandstones, the latter being either green or grey, and the shales and claystones 
either yellowish- white or else dull bluish-green when fresh, in which latter case they weather 
to a chocolate colour. In the shales and claystones are frtvjuently found hard spherical con- 
cretions, varying in diameter from 1 in. or less to 5 ft. or 6 ft. These concretions are mostly, and 
in the case of the larger ones always, calcareous, and frequently contain fossils. Under the 
microscope they are found to be made up of a quartz sand containing a few small feldspars 
cemented together by about an equal amount of calcite. In some localities, however, espe- 
cially in the Takou River in close proximity to igneous intrusions, at Ferguson Point, in the 
upper Waitetoki Creek, and in Landslip Creek, the smaller concretions are largely or wholly 
composed of pyrite and marcasite, but contain no minerals of value. The nodules from the 
Takou River contained 68-28 per cent, of iron-sulphide, partly, if not wholly, in the form of 
marcasite. 

4* — Whangaroa. 



5'Z 

An anlaysis of impure nodules of iron- sulphide from the shales in Hare's No. I drive, 
Pupuke Copper-field, is as follows : — 



SiUca (SiOj 


50-35 


Alumina (AI2O3) .. 


7-41 


Ferric oxide (FegOg) 


0-50 


Lime (CaO) 


1-98 


Magnesia (MgO) 


2-60 


Iron-disulphide (FeSj) 


3005 


Water, organic matter, and undeteruiLned 


7-11 



10000 

The nodules, though found in this case in the neighbourhood of a cupriferous vein, contain 
no copper, silver, gold, or other metal of value. 

The rapidly alternating sandstones and shales of the Pupuke and Waihapa basins appa- 
rently grade upwards into thicker and more persistent beds of a blue-grey calcareous claystone, 
which nearly always breaks into small lenses with polished slickensided surfaces. This type is 
well exhibited in the Pupuke Copper-field and its neighbourhood, and again in the Waitangi 
River. 

The following analyses of typical samples of shales give a general idea of the chemical 
constitution of these members of the series : — 





No. 1. 


No. 2. 


No. 3. 


No. 4. 


No. 5. 


SiUca(Si02) 


. 51-74 


44-25 


47-95 


48-81 


50-25 


Alumina (AI2O3) 


. 20-06 


21-63 


23-25 


22-28 


22-17 


Ferric oxide (FejOj) 


3-44) 


7-90* 


7-60* 


7-60* 


4-88= 


Ferrous oxide (FeO) 


8-64 [ 










Lime (CaO) 


3-40 


9-47 


4-83 


903 


3-60 


Magnesia (MgO) 


3-70 


4-10 


1-80 


2-00 


4-80 


Iron-disulphide (FeSa) . . 


0-27 


3-32 








Carbonic anhydride (COj) 


. 




2-60 


0-37 


. . 


Titanic oxide (TiOa) 


. 






0-95 




Loss on ignition (excluding sulphur 


5-25 




8-55 


4-82 


12-55 


Potash (K2O) . . 


- ] 


i- 9-33 


1 


1-06 


) 


Soda (NajO) 


. ■ 3-50 


«/ tJ*J 


- 3-42 


3-08 


>- 1-75 


Undetermined . . 


■J J 




) 


•• 



10000 



100-00 



10000 



100-00 



100-00 



No. 1 is a greenish, slickensided, apd somewhat mineralised shale from the Ferguson 
Company's drive in Stirling Creek. 

No. 2 is a blue mineralised shale from Thursday Creek. 

No. 3 is a blue carbonaceous shale from Awaiti Creek. 

No. 4 is a shale from No. 3 drive, WTiangaroa Amalgamated Claim, Pupuke Copper- 
field. 

No. 5 is a carbonaceous shale in close contact with an andesitic dyke from the Takou 
River near the eastern boundarv of the subdivision. 



* In these analyses no separate determination wa« made for ferrous oxide. 



53 



5-78 


0-56 


0-21 


044 


0-75 



The hard, flaggy sandstone from near Mr. J. Hare's house has the following composition 

Silica (SiOJ . . . . . . . . . . . . 92-26 

Iron-oxides (FeO and FeoOg), alumina (AI2O3), phosphoric 

anhydride (PjOg), &c. 
Lime (CaO) 
Magnesia (MgO) 
Carbonic anhydride (CO 2) 
Moisture and organic matter 

10000 

A sample of this stone was submitted to Mr. R. C. Aston, the Chief Chemist of the Agricultural 
Department, and is reported by him to contain "a small quantity (1-2 per cent.) of phos- 
phoric acid." 

The shaly limestones of this part of the Kaeo Series, occurring in the northern area of 
Kaeo rocks, differ from the massive limestones found in the southern area in being more 
impure and in being frequently softer and incoherent. 

Massive Limestones. — The limestones of the southern area are generally massive and 
even-grained, but rather soft rocks showing well-defined stratification, and are in places re- 
peatedly interbedded with glauconitic greensands. The following analyses show the range 
in their composition : — 





No. 1. 


No. 2. 


No. 3. 


No. 4. 


No. 5. 


SiUca(Si02) 


I4--25 


37- 10 


22-10 


49-67 


18-53 


Alumina (AI2O3) 


3-66 


1-54 


2-29 


8-31 


2-66 


Ferric oxide (FejOj) 


3-88 


301 


2-96 


2-56 


1-52 


Lime (CaO) 


. 43-25 


32-80 


37-52 


17-58 


39-90 


Magnesia (MgO) 


0-15 


110 


0-85 


1-31 


0-88 


Carbonic anhydride (CO,) 


33-(i5 


22-84 


29-47 


13-82 


31-43 


Water and organic matter 


0-45 


0-56 


2-21 


5-66 


2-24 


Alkalis and undetermined 


0-71 


105 


2-60 


1-09 


2-84 



10000 



10000 



100-00 



10000 



10000 



No. 1 is a white limestone from the lower part of the Waikaraka Stream, about a mile 

above its junction with the Whakanekeneke River. 
No. 2 is an impure arenaceous limestone from Pirau Stream, about 30 chains north-west 

of Trigonometrical Station M. 
No. 3 is an arenaceous limestone from Awahei Creek, about a cjuarter of a mile above its 

junction with the Waitangi. 
No. 4 is an arenaceous limestone, or perhaps more correctly a calcareous sandstone, 

from the Waitangi River, about a quarter of a mile below its junction with the 

Awahei. 
No. 5 is an arenaceous limestone from the Waikaraka River, about half a mile north of 

the Waimate-Okaihau Road. 



54 

The argillaceous limestone found in the Upper Waitangi about half a mile above its junc- 
tion with Willis Creek, and in many other places in the neighbourhood, contains large white 
flinty concretions, which analyse as follows : — 



Silica (SiOa) 


.. 88-11 


Alumina (AI2O3) 


2-01 


Ferric oxide (FcoOg) 


6-60 


Lime (CaO) 


1-30 


Magnesia (MgO) 


040 


Carbonic anhydride (CO 2) 


0-54 


Water and organic matter 


002 


Alkalis and undetermined 


102 



10000 



Greensands. — The greensands are very constant in petrological characteristics, differ- 
ing but little throughout the subdivision in the coarseness of their component grains, though 
there is a considerable variation in the percentage of secondary calcite, silica, &c. At various 
places near Kaeo the greensands are seen to contain abundant but very poorly preserved 
molluscan fossils. The zone of silicified rock already mentioned lies partly perhaps in the 
greensands, though mainly apparently associated with the tuffs, with which the greensands 
are easily confused in the field. 

Microscopic examination shows the greensands to consist mainly of quartz, with which 
is associated much unidentifiable opacite and a greenish mineral proved by chemical analysis 
to be glauconite. Granules of pyrite are of common occurrence. Analyses of — (1) a typical 
specimen of greensand from Packhorse Creek, a tributary of Oika Creek ; and (2) a bleached 
greensand from the Kerikeri River, about three-quarters of a mile inside the boundary of the 
subdivision, are as follows : — 



Silica (SiO 2).. 
Alumina (AljOg) 
Ferric oxide (Fe2 03) . . 
Lime (CaO) . . 
Magnesia (MgO) 
Carbonic anhydride (CO 2) 
Water and organic matter 
Alkalis I 

Undetermined I 



No. 1. 


No. 2. 


70-20 


67-25 


13-73 


19-80 


3-60 


1-15 


0-95 


0-20 


1-40 


0-10 


Nil 


Nil. 


5-54 


10-20 


4-58 


1-30 



10000 



100-00 



In these analyses no separate determination was made for ferrous oxide, but microscopic 
examination of the rocks shows that glauconite is present. 

The following analysis of a rather coarse, impure, and mineralised greenish sandstone 
from the upper part of the Whakateterekia River, a little over half a mile above Mr. Foley's 



55 

house, in close proximity to an intrusion of gabbro, is interesting as showing a small copper- 
content : — 



Silica (SiO^) 










79-90 


Alumina (AlgOg) 










7-81 


Ferric oxide (FegOg) 










3-80 


Lime (CaO) 










0-95 


Magnesia (MgO) 










1-90 


Carbonic anhydride (COj) 










Nil. 


Water and orj^anic matter 










2-85 


Alkalis and uTuleterniined 










2-31 


Copper 










048 



10000 

Seams of white, banded, opaline silica are found in the fjreensands ex{)()sod in the Kcrikori 
River. 

Calcareous Saudfttones. — In hand-specimens the calcareous sandstones are compact, white 
or grey rocks, often highly siliceous and splitting readily into flags. 

The following analyses show the range in composition of the calcareous sandstones : — 





No. 1. 


No. 2. 


No. 3. 


Silica (SiOa) 


8142 


88-32 


2710 


Alumina (AUOg) 


8-32 


1-79 


401 


Ferric oxide (FejOj) 


1-68 


5-91 


2-32 


Lime (CaO) 


2-30 


1-67 


3.5 -fil 


Magnesia (MgO) . . 


010 


010 


015 


Carbonic anhydride (C()„) 


0-90 


O-.'iO 


26-70 


Water and organic matter . 


3-74 


1-31 


2-32 


Undetermined 


1-54 


0-40 


1-79 



10000 



10000 



100 00 



No. 1 is a calcareous sandstone from Inumia Creek, about half a mile l)elow its junction 

with the Kiti Tawa. 
No. 2 is a calcareous sandstone from the ridge between the Waikoura and Pahuhu creeks. 
No. 3 is an impure limestone from Towai Creek, about half a mile above Towai 

Settlement. 



(f.) PALEONTOLOGY. 

Fossils are found at three horizons in the Kaeo Series — in the conglomerates, in the con- 
cretionarv shales and sandstones, and in the greensands. Very occasionally the concretionary 
shales and sandstones yield well-preserved fossils. It is very rare to find anything but imperfect 
casts in the greensands, while in the case of the conglomerates of Mangapukahukahu Creek 
the shells are too fragmentary to be at all identifiable. 



56 

Fossils of the Concretionary Shales and Sandstones. 

Obscure remains in the mudstones of the Pupuke near the mouth of Te Patoa Creek, and 
in the fine sandstones of the Inuinia about half a mile below its junction with the Kiti Tawa 
Creek, appeared to be ammonites. Better-preserved fossils are found in calcareous concretions 
in two localities along the shore-line of WTiangaroa Harbour — namely, between Sales and the 
Iwitaua Bridge, and on the ^\^langaroa side, near Mr. .J. Nelder's house, in Waitapu Bay. 
In both places the concretions have to be broken open on the chance of finding fossils within, 
and, owing to the hardness of the matrix, it is difficult to make a clean separation of the fossils 
from the enclosing stone. The number of identifiable fossils is therefore small. The following 
list includes all those specimens at all describable : — 

Anthozoa. (Plate XII, Fig. 2.) 
A few specimens of a member of the hexacoralla were found near Mr. J. Nelder's house. 
It was possible to examine these specimens only by means of cross and longitudinal sections. 
The indi\'iduals were solitary. Corallura apparently elongated, conical, and slightly recurved. 
Circular in cross-section. Theca, thin. Septa, in the specimens obtained, in two cycles of 
six each. The septa of the first cycle meet in the centre, where there is a fairly stout 
columella. Diameter, 6 mm. Greatest length observed, 18 mm. 

Pdecypoda. 

Trigonia ? (Plate XII, Fig. 1). — Shell subtrigonal, rather compressed. A slight ridge 
runs from the umbo to the posterior-lateral margin. The shell has about eighteen smooth, 
rounded, concentric ridges, the same width as the intervening furrows, very distinct and well 
marked towards the margin, less clear towards the um])o, the last part of which mthin a radius 
of 6 mm. is damaged, and shows only faint traces of them. Length, 36 mm. Breadth, 26 mm. 
Only a single specimen was obtained. 

Amussium ? — Only a portion of one specimen showing the umbo and a portion of one ear 
was obtained. The shell might be a portion of a form allied to A. zitteli, but, without 
better specimens, no definite identification could be attempted. 

Venus ? — A single imperfectly preserved shell was found, which may belong to this genus. 

TJnio. — A very imperfect cast so named is in the Auckland Museum. 

QasiroipodLa. 
Remains of at least two species are occasionally found in the calcareous nodules, but 
the specimens so far obtained are too fragmentary for further identification. 

CfphaloTpoAa. 

Desmoceras ? (Plate XII, Figs. 3a and h). — Shell spineless, closely coiled, but the older 
coils not much hidden by the younger. Shell crossed transversely by simple sharp ridges, 
varying a good deal in closeness, but usually 1-5-2 mm. apart. 

Fairly abundant at Saies, and near Mr. J. Nelder's house. 

Appears to belong to Zittel's Haploceratidce, and may be Desmoceras. So far as could 
be seen, however, the siphonal saddles do not agree with the characters of this family, but 
unfortunately this portion of the suture was destroyed in all but one of the Whangaroa 
specimens, and in that one was indistinct. 

The A\Tiangaroa species exactly agrees with specimens in the Auckland Museum from 
Hokianga. It also resembles one in Professor Marshall's collection from the Hokanui Hills, 
but is more finely sculptured. 

Probably closely related to the above are two other species, in both of which the younger 
coils overlap the earlier much more completely. 



PLATE XII. 









I; 

V 



A 



i ; c^" 




3 a/ 




'<<. 




^' 



<.>^ 



\ 



^ :. 



•^ 6 






\-., 



L. 



% 



•v \ 





A 




Fossils of the Kaeo Series. 

A. Fossils of thk C'oncrktionary Shalks. 
1. Trigtmia sp., natural size. 
•2. Coral in transverse section, x 2. 

a. (rt.) Desmoceran sp., x 2. (?<.! Dexmoceran suture, x about 7. Mouth of shell is facing upwards 

ventral portion of suture (to left), though shown in drawing, is not clear in specimens. 

4. Small cephalopod (?i, x 2. (In Auckland Museum.) 

5. Haviites sp. Portion of an individual, x 2. 

6. Imperfect cast of one side of a cephalopod, natural size. (In Auckland Museum.) 

B. Fossils of the Grkensands. 

7. Ostrea sp., natural size. 
H. Oxi/rhina von haastii. 

(a.) Inner side of tooth, natural size. (6.) Outer side of tooth, natural size. 



Ilullttin No. «.] 



[Face f. 56. 



57 

One of these species is 60 mm. in diameter, and has apparently the same ribbing and 
sutures as the form already described, but shows a tendency to the development of tubercles 
along the inner (dorsal) edge of the outermost coil (the only one visible), and is also much 
more involute. 

The sutures of the second species are not distinct, and its relationships are therefore 
not certain. It was apparently smooth, and is also more strongly involute than the specimen 
described as Desmoceras. 

In the Auckland Museum is a small cephalopod (length, 11 mm. ; breadth, 8 mm.) from 
Sales, in which the last whorl is strongly involute, almost concealing the earlier ones. No 
sutures are visible on this shell, but there are faint indications of fine transverse striae. 
(Plate XII, Fig. 4.) 

In the Auckland Museum is also a cast of a portion of an ammonite from Sales. This 
species bore spines on the dorsal edges of the coils. The coils were also traversed by strong 
transverse curving ribs. (Plate XII, Fig. 6.) 

The specimen is too fragmentary for further identification, but is interesting as indicating 
the presence of highly dift'erentiated anuuonoids. This species may belong to Hyatt's sub- 
order Pachycampyli. 

ffamites ? (Plate XII, Fig. 5). — Fragments of an uncoiled cephalopod arc abundant in the 
calcareous concretions. The shell is transversely ribbed with numerous fine stria'. No 
sutures are visible in the specimens so far obtained. 

Belemnites. — In breaking open the concretions near Sales a few cylinders of graimlar cal 
cite 20-23 mm. in diameter, and of undetermined length, were found. It is doubtful whether 
these really are belemnites, since no radial structure could be distinguished on polishing the 
transverse sections. In the concretions at Nelder's, cylindrical or taj)eriiig tubes occasionally 
showing radial structure in cross-sections ought probably to be assigned to the belemnites, 
but no forms resembling them seem as yet to have been described from New Zealand rocks. 

In addition to the foregoing specimens, fragments of carbonised wood, both monocoty- 
ledonous and dicotyledonous, are fairly frequent in the calcareous concretions. 

Fossils of the Greensatids. 

Ver\- poorly preserved casts of marine shells occur in the grcensands in manv places in 
the neighbourhood of Kaeo. These are seldom recognisable beyond being Gastropods or 
Pelecvpods. Casts of a Turritella, agreeing best with T. ambulacrum, are plentiful. This 
species is reported only from Pareora (Miocene) strata. 

From the greensands in Waionepu Creek a fairly well-preserved specimen of an Ostrea, 
apparently a new species, was obtained (Plate XII, Fig. 7). 

From the same locality was secured a single shark-tooth which resembles Oxyrhina von 
haastii (Davis),* but does not altogether agree with Davis's description (see Plate XII, 
Figs. 8o and b), more particularly in respect to the proportions of the root. Nevertheless, a 
careful comparison with the original of Davis's Fig. 3, Plate IV, in the Dominion Muscmm at 
Wellington, and a consideration of the variation shown by the specimens in his Fig. 1 , seem 
to justify its inclusion with this species. 

Hector, in his " Critical Notes on Mr. Davis's Paper, "f takes exception to the list of 
localities for 0. von haastii, but, in the table showing the distribution of the species at the end 
of his " Critical Notes," marks it as occurring only in the " Oamaru formation " which over- 
lies his " Upper Cretaceo-Tertiary VI." 

• " Fossil Fish-remains from Tertiary and Cretaceo-Teitiary Fcrmations of New Zealand," Scientific 
Trans, of Royal Dublin Soc, vol. iv, ser. ii, 1888. 

t Rep. G.S. during 1892-3, No. 22, 1894, p. 115, &c. 



58 

(/.) CORRELATION AND AGE. 

Unconformity between the Kaeo Series and the older Waipapa rocks, as abeady men- 
tioned, was observed at Pa Island, at the north-western end of Taupo Bay, at various places 
on Whangaroa Harbour, in several of the streams flowing into the harbour from the west, 
in the upper waters of the Whakateterekia and Inumia, and in the Mangapukahukahu and 
Pirau creeks. 

In most of these places conglomerates containing fragments of the older rocks are found, 
succeeded by Kaeo rocks. In one or two cases the conglomerate is apparently absent, and 
finer-grained fragmental rocks or limestones are found lying directly on the denuded surface 
of the Waipapa rocks. 

In the section on palaeontology it has been shown that the lower beds of the Kaeo Series 
contain fossils of a Cretaceous aspect. Owing to the scanty detailed information on the Meso- 
zoic faunas of New Zealand, it is not at present possible to correlate the Kaeo rocks with others 
in the Dominion. Professor Marshall has, however, informed the writers that, judging from 
hand-specimens of the Whangaroa rocks, this portion of the Kaeo Series bears a considerable 
resemblance to the Mesozoic rocks at Kawhia Harbour, on the west coast of the North Island. 

From the few fossils found in the Kaeo greensands they have always been regarded as of 
Tertiary age. In the section on the structure and detailed distribution of Kaeo rocks it has 
been pointed out that no certain stratigraphical break has been recognised between the 
concretionary shales and the greensands. Professor Marshall informs the writers that 
greensands unconformably overlie the Secondary rocks at Kawhia Harbour. It therefore 
seems possible that further investigation will establish the equivalence of the Kaeo Series 
and the rocks exposed at Kawhia Harbour. 

The late Sir James Hector and other officers of the former Geological Survey of Ne-s*' 
Zealand maintained that " Cretaceo-Tertiary " rocks, bridging over the gap between Mesozoic 
and Tertiary times, are widely distributed throughout the Dominion. Other geologists — 
notably, Professor Hutton — contended that these " Cretaceo-Tertiary " rocks may always be 
separated into distinct Mesozoic and Tertiarv- portions. A large number of papers has been 
written on this question, but in those by Professors Hutton and Park on the ages of the New 
Zealand coalfields* a full discussion of the problem and list of hterature bearing on it will 
be found. It will be seen that in the Whangaroa Subdivision the sum-total of the evidence 
favours the view that the Kaeo Series should be divided into an older portion of Mesozoic age 
and a yoimger portion of Tertiary age, or, in other words, that a Cretaceo-Tertiary system is 
not represented. It has, however, been considered advisable, until more extended observa- 
tions have been made in this part of New Zealand, to group these possibly distinct series 
together under the name Kaeo. (See also page 49.) 

Ngawha Lake Beds. 
The insilted Ngawha Lake basin (see detailed map) lies in the south-east corner of the 
subdivision, and covers an area of about two and a half square miles. The lake was formed 
by the ponding-back of the headwaters of a stream which flowed eastward near the present 
site of Ngawha Settlement, either by flows of lava from the old volcano, the remnant of which 
is represented by the high land between Tarahi and Putahi, or more probably by Kerikeri 
flow rocks now, save for a few isolated outcrops, covered by the later flows. The lake was 
ponded up until it overflowed in two places at low saddles in the ridge of Kaeo rocks south 
of Ngawha. It gradually disappeared, partly by insilting, and partly by drainage due to 
cutting back by the effluent streams (the Manga tawai and Ngawha). During the last stages 



* Hutton, " On the Ages of the New Zealand Coalfields," Trans., vol. xxii, 1889, p. 377 ; Park, " On 
the Age and Relations of the New Zealand Coalfields," Trans., vol. xxvi, 1903, p. 405. See also Park, " On 
the Marine Tertiaries of Otago and Canterbury," &c.. Trans., vol. xxxvii, 1904, p. 489. 



59 



of its history the lake was largely converted into a swamp, in which deposits of peat formed. 
Little information as to the character of the vegetation which contributed to the formation 
of the peat is to be obtained from an examination of the deposits. Remains of raupo (Typha 
angustifolia) leaves are common, and the abundant fragments of kauri {Agathis australis) 
and manoao (Dacrydium kirkii) indicate that probably, during the final stages of its dessica- 
tion, the lake-basin was covered with a dense forest of these trees. The denuded remnants 
of these deposits are represented on the map, and further information will be found in 
Chapter VI, pages 95, 96. 

As already mentioned, the ponds scattered about the surface of the lake-basin are explo- 
sion-craters, probably contemporaneous with the latest volcanic eruptions of the district. 

The materials by which the lake is filled are well exposed in the mine-excavations at 
the mercury-deposits, and again at places on the Mangatawai Stream. The beds consist 
of irregularly stratified, highly carbonaceous sands and clays, and less common, coarse, uncon- 
solidated, and sometimes angular grits, made up chiefly of fragments of sedimentary rocks 
of Kaeo age, but sometimes containing fragments of volcanic rock agreeing in microscopic 
structure with the dolerites of the Kerikeri Series. 

The following analysis for hydrocarbons was made of the carbonaceous clays which have 
been disclosed in the mine-workings just below the No. 1 area of the det^iiled map, and from 
which the petroliferous springs of No. 2 area doubtless derive their carbon. The shales prove 
to contain too low a percentage of hydrocarbons to be of value for the extraction of mineral 
oil:— 

Fixed carbon . . . . . . . . . . . . 207 

Volatile hydrocarbons . . . . . . . . 7-37 

Water .. .. .. .. .. .. .. 2-31 

Ash .. .. .. .. .. .. .. 88-25 



10000 



The following is an analysis of atypical sample of a stratified, carbonaceous, and aluminous 
sand from No. 5 area (see detailed map). Although there were no visible signs of altera- 
tion, no doubt the gases escaping from vents in the neighbourhood have considerably modified 
the composition of this rock, especially in increasing the percentage of iron-disulphide : — 

Silica (SiOj) . . . . . . . . . . 42-30 

Alumina (AI2O3) 

Ferric oxide (Fe^Oj) 

Lime (CaO) 

Magnesia (MgO) 

Potash (K,0) 

Soda (Na^b) 

Titanic oxide (TiOj) 

Iron-disulphide (FeS J 

Carbonic anhydride (CO 2) 

Water and organic matter 

10000 

High-level River-terraces. 
The denuded remains of old river-terraces 60 ft. or more above the present level of the 
rivers occur in the Pupuke River as far upstream as the neighbourhood of the Matawherohia 
Junction, and in the lower parts of the Whakanekeneke^and Waikaraka rivers. These ter- 
races are in the main composed of incoherent gravels, sands, and muds irregularly interbedded. 







. . 21-35 






. . 0-20 






2-20 






1-80 






. . 0-96 






319 






040 






. . U-43 






Nil. 






.. 1317 



60 



Recent Deposits. 
The Recent Deposits may be classified as — 
(a.) Hot and cold spring deposits. 
(6.) Fluviatile deposits,^ — 

(1.) Alluvial flats. 

(2.) Swamps, 
(c.) Lacustrine deposits. 
(d.) Fluvio-marine and marine deposits, — 

(1.) Estuarine deposits (tidal flats). 

(2.) Sand and other marine detritus. 



(a.) HOT AND COLD SPRING DEPOSITS. 

A low mound of sinter, 1 chain or more in diameter, has accumulated in the neighbourhood 
of Neilson's soda spring at Ngawha, being partly deposited by the waters of the present spring 
and partly by another spring which has now ceased to be active. The following is the com- 
position of this sinter : — 

Silica (SiOJ 

Iron-oxides and alumina (FeO, FcjOg, 

Manganous oxide (MnO) 

Lime (CaO) 



AI2O3) 



Magnesia (MgO) 
Carbonic anhydride (CO 2) 
Water and organic matter 
Undetermined (alkalis, sulphur, &c.) 



92-15 
2-58 
0-05 
015 
0-20 
015 
3-73 
0-99 

10000 



The sinter also contains 8 gr. of gold and 1 dwt. 6 gr. of silver per ton. 

A general sample of the silicified sintery sands from the neighbourhood of the warm spring 
in Area 4 of the Ohaeawai Hot Springs (see Chapter III, page 38) was examined for metals, 
with the following results : Gold, nil ; silver, nil ; mercury, nil ; antimony-trisulphide 
(SbjSg), 0-05 per cent. ; manganous oxide, 0-07 per cent. 

A few chains from the Ohaeawai-Okaihau Road, near Mr. J. D. Kemp's house, there 
occurs at the head of a small swamp a moimd of red ochre deposited by a spring which occupies 
a small basin on the summit of the mound. A very small deposit is being formed round the 
CO2 spring on Waikoura mud-flat, and similar deposits in the same neighbourhood testify 
to the former presence of other springs. An analysis of the sinter formed by the spring at 
present active is as follows : — 

Silica (SiO 2) .. .. .. .. .. 313 

Iron-oxides and alumina (FeO, FegOj, AI2O3) . . . . . . 2-07 

Lime (CaO) . . . . . . . . . . . . 51-70 

Magnesia (MgO) . . . . . . . . . . . . 0-30 

Carbonic anhydride (CO2) . . - . . . . . . . 39-26 

Water and organic matter . . . . . . . . . . 2-10 

Undetermined (alkalis, sulphur, &c.) . . . . . . . . 1-44 



10000 



The sinter also contains 1 gr. of gold per ton and 0-2 per cent, of manganous oxide. A larger 
deposit is forming on the left bank of the Tangitu Creek, a short distance above its jimction 



(31 

with the Pupuke. As shown by the partial analysis below, it is composed chiefly of calcium- 
carbonate leached out of the neighboiiring greensands : — 

Per Cent. 
Ferric oxide (FcjOa) .. .. .. .. .. 317 

Lime (CaO) .. .. .. .. .. .. 51-11 

Carbonic anhydride (COj) . . . . . . . . . . 40-20 

The hot and warm springs of the Ngawha Lake basin are depositing sinters, further details 
regarding which will be found in Chapter VI, page 87 et seq. 

Small deposits of sulphur arc also of frequent occurrence in the Ngawha Lake basin, 
and in the other places in the south-east corner of the subdivision in which hydrogen-disul- 
phide vents occur. 

On some of the pools on the right side of the small cool stream which traverses No. 2 area 
floats a thick scum of petroleum, which in jjlaces has solidihed around the edges in mam- 
millary forms with jet-like fracture. This solid hydrocarbon is of the following composi- 
tion : — 

Fixed carbon .. .. .. .. .. .. 121 

Hydrocarbons . . . . . . . . 47-6 

Loss at 100° C. . . . . . . . . . . . . 3-7 

Ash .. .. .. .. .. .. .. 36-6 



100-0 



" When distilled the sample yielded appro.ximately 20 per cent, of oil and tar. It was, how- 
ever, too small to allow of these being separated, or of the total yield being estimated with 
any degree of accuracy."* 

The following is an approximate analysis by Mr. W. Skey| of " a deposit formed by these 
springs " (the exact locality of the deposit is not given) : — 

"Sulphur .. .. .. .. .. .. .. 83-37 

Siliceous matter . . . . . . . . 16-33 

Soluble salts and acids . . . . . . . . . . 0-30 



The soluble part when analysed proved to be composed as follows :- 
" Sulphate of alumina 



iron 



,, lime with a little sulphate of magnesia 

Free hydrochloric acid 
,, sulphuric acid . . 
Alkaline sulphates and loss 



10000 

. 52-43 
. Traces. 
. 27-60 
. Traces. 
. 11-32 
8-65 

10000 " 



(6.) FLUVIATILE DEPOSITS. 
(1.) Alluvial Flats. — These are of wide distribution throughout the subdivision, but are 
never very extensive. Their extent has already been described in Chapter III. The most 
abundant constituents of these alluvial deposits are gravel and silt formed from Waipapa 
and Kaeo rocks. Boulders of volcanic rock occur in most of the streams, and are very 
abundant in some — notably, the headwaters and tributaries of the Waitangi River. 



♦ From report by Dr. J. S. Maclaurin, Dominion Analyst. 

t " On Ortain of the Mineral Waters of New Zealand," Trans., vol. x, 1877, p. 425. 



62 

(2.) Swamps. — These are described in Chapter III. Deposits of bog iron-ore, of whicli 
some analyses will be found in Chapter VI, page 94, are forming in inauy of them. 

(C.) LACUSTRINE DEPOSITS. 

These are limited to the swamps which occur round the margin of Lake Omapere, par- 
ticularly at its eastern end, and which are found also round the margins of most of the ponds 
in the Ngawha Basin — particularly Tuwhakino and Ngamokaikai — and to the deposits which 
are accunmlating in these lakes. Most of the ponds formerly stood at a higher level than at 
present, and have been partially drained by the back-cutting of the effluent stream. The 
terraces which mark the former level of the water of the various ponds should, perhaps, be 
classed with the newer debris. 

The deposits of sulphur probably accumulating in Waiparaheka Pond, in Waitetera 
Pond, in the sulphur ponds on a branch of the Mangatawai Stream, and in the small pond 
draining into No. 4 area (see detailed map) will be referred to in Chapter VI. 

Ordinar}'^ silts are accumulating in the other, ponds and in Lake Omapere. 

(d.) FLUVIO-MARINE AND MARINE DEPOSITS. 

(L) Estuarine Deposits {Tidal Flats). — ^Under this head are placed the tidal mud- flats, 
largely covered with mangroves, which occupy an area of a little over four square miles in 
Whangaroa Harbour. These flats are composed of a grey calcareous mud of unknown but 
■considerable depth. In the part of the swamp nearest the land, and now covered only by the 
highest tides, occur large beds of shells of Chione stutchburyi — the pipi of the northern 
Maori — which formerly flourished here. Similar banks of living pipis are found near the 
outer low-tide margin of the mud-flats. Very much smaller tidal flats are found near the 
mouths of the Tauranga and other streams. 

(2.) Sand and Other Marine Detritus. — Small sand-deposits, somewhat reassorted by 
wind, occur in Tupo, Taupo, Tauranga, Mahinepua, Wainui, and Tangaire bays, but the extent 
of these accumulations is always small. Gravel beaches occur chiefly in the small bays on the 
exposed promontory between Taupo and Tupo bays. The sand is a yellow shell-sand, made 
up of granules of quartz and other minerals mixed with an abundance of comminuted shell- 
fragments. The gravel and boulder beaches are composed of rounded fragments of the 
igneous or sedimentary rocks in the neighbourhood. 



03 



CHAPTER V. 



IGNEOUS ROCKS.* 



Introductory 

1. Contemporaneous Igneous Rocks of 

the Waipapa Series . . 
(a.) Structure and Distribution 
(6.) Petrology 

2. The Wairakau Scries 

(a.) Structure and Distribution 
(b.) Petrology 

(c.) Secondary Siliceous Deposits 
(d.) Correlation and Ago 
(e.) Conditions and Foci of Erup- 
tion 

3. The Kerikeri Series 

(a.) Structure and Distribution 
{h.) Petrology 

(c. ) Ix)cal Aqueous Deposits 
{d. ) Correlation and Age 



•ago 

63 


3. 


The Kerikeri Series — contimied. 


03 


4. 


(e.) Conditions and Foci of Eruption 
Acidic Igneous Rocks 


03 




(a.) Structure and Distribution .. 


04 
05 


5. 


(b. ) Petrology 
Later Basic \olcanics 


05 




(a.) Structure and Distribution . . 


66 
68 


0. 


(6.) Petrology 
Igneous Rocks of Doubtf\il Ago . . 


08 




(a.) Igneous Rocks, either Waira- 
kau or Kerikeri in Age 


09 
69 
69 
70 
71 
72 




(b.) Igneous Rocks, I'ost-Wai- 

])apa and probably Post- 

Kaco in Age 

(c.) Igneous Rocks younger than 

thos<i of the preceding 

Section 



72 

72 
72 
73 
74 
74 
74 



75 



76 



78 



Introductory. 

As a rule, the igneous rocks of the Whangaroa Subdivision, though having a wide range in 
time, show little variation from a semi-basic or basic composition. There are, indeed, occur- 
rences of acidic rocks, but these, though of interest, are of very minor extent. 

The subject-matter of this chapter may most conveniently be subdivided as follows : — 

1. Contemporaneous igneous rocks of the Waipapa Series. 

2. The Wairakau Scries. 

3. The Kerikeri Series. 
•1. Acidic igneous rocks. 

5. Later basic volcanics. 

6. Igneous rocks of doubtful age, — 

(a.) Igneous rocks, either Wairakau or Kerikeri in age. 

(h.) Igneous rocks, post- Waipapa and probably post-Kaeo in age. 

(c.) Igneous rocks younger than those of the preceding section. 

Very minor beds of non-pyroclastic sedimentary rooks, intimately associated with the volcanics 
of the Wairakau and Kerikeri volcanics, should strictly have been considered in Chapter IV, 
but are more naturallv discussed h(?re. 



1. Contemporaneous Igneous Rocks ok the Waipapa Series. 

(fl.) Structure and Distribution. 

The igneous rocks of the Waipapa Series consi.st of basic Hows, tuffs, and breccias which 
are interbedded with the sedimentary rocks of the series, and may be traced in fairly con- 



* Together with minor non-pyroclastic sedimentarj dcijosits intimately associated therewith. 



64 

tinuous bands in both the coastal and inland exposures of Waipapa rocks. These bands have 
the same general trend as the sedimentaries, but, owing partly to original irregularities in 
deposition and more largely to subsequent distortion and dislocation, they are frequently 
interrupted. 

In the coastal area a single belt of sedimentary rocks, containing numerous flows of igneous 
rocks, occurs. It runs from the high land at the head of Tangaire Creek in a generally W.N.W. 
direction to the north-west end of Stephenson Island, and has frequent exposures in the 
intervening space, especially on the coast from Kairauwaru Bay to Arrow Rock. 

It is only in the coastal area that contemporaneous breccias and tufis occur in any abund- 
ance, their main development being on the coast-line on both sides of Kairauwaru Bay and 
on Oruatemanu Island. A very compact tufaceous rock was, however, obtained from the 
Waipapa River about two miles above its junction with the Whakanekeneke. 

The two most important exposures of igneous rocks in the inland Waipapa area pro- 
bably belong to separate horizons. They are, first, on the Waipapa River, between the mouths 
of the Pukatea and Waikape creeks, and at intervals throughout the courses of the latter 
streams and their branches, and also in that of the Onekura ; and, secondly, in a band stretch- 
ing from the upper waters of the Mangakino to the Whakateterekia just at and above its junc- 
tion with the Mangakino. These bands, in common with the sedimentary rocks of this inland 
area, have a general W.S. W. and E.N.E. trend. Much-altered igneous rocks contemporaneous 
with the Waipapa sedimentaries also occur in Paripawa Creek, a quarter of a mile above its 
junction with the Tangitu and thence at intervals to its soujce, in Nip Creek, about half a 
mile above its junction with the Mangakino, and at the headwaters of the two main branches 
of the Whakateterekia. 

(b.) Petrology. 

Petrologically the igneous rocks of the Waipapa Series are olivine-basalts, which are 
frequently amygdaloidal. In the field the flows appear as very compact and fine-grained 
rocks, and are nearly always red or tinged with red. Their crystalline structure is usually 
very much obscured owing to subsequent alteration. Occasionally amygdules of calcite 
are abundant and conspicuous. The breccias are made up of angular fragments of reddened 
and indurated amygdaloidal igneous rock embedded in a rather soft, green, fissile matrix, 
which contains much calcite and chlorite. 

Microscopically the prevalent type of basalt consists mainly of a felt of elongated feldspars, 
usually not exhibiting any direction of flow, but often showing a rough concentric arrange- 
ment and a curving of the individuals round one another, the latter phenomenon being possibly 
due to later regional movement. The feldspars are nearly always entirely decomposed to a 
mass of minute calcite grains, but occasionally show signs of multiple twinning. The 
remainder of the section is usually obscure, but between the feldspar laths there may some- 
times be distinguished granules of altered augite and, more rarely, of serpentinised olivine. 
Secondary calcite is abundant, filling vapour cavities and forming microscopic veins through 
the rock. The characteristic red colour of the rocks is found to be due to great numbers of 
minute granules of limonite scattered through the groundmass. 

Olivine is not commonly identifiable, but in one section from an exposure on the east 
side of Kairauwaru Bay, where the alteration is much less pronounced, it may frequently 
be seen. A section of a very similar roc]< from a neighbouring exposure was remarkable as 
showing reddish-brown monoclinic pyroxenes. This colouration is said by some petrologists 
to be due to the presence'Tof manganese.^' )^ It is noteworthy that small stringers of impure 
manganese-ore are common in the neighbourhood. 



65 



Typical samples of the igneous rocks — (1) from the northern end of Stephenson Island, 
(2) from the coast-line near the base of Omiru Peninsula — have the following compositions : — 

Silica {SiOa) 
Alumina (AI2O3) 
Ferric oxide (FejOg) 
Ferrous oxide (FeO) 
Lime (CaO) . . 
Magnesia (MgO) 
Iron-disulphide (FeSj) 
Potash (K2O) 
Soda (Na^O) 
Titanium- dioxide (TiOj) 
Carbonic anhydride (CO 2) 
Water and organic matter 



No. 1 


No. 2. 


43-56 


46-82 


18-88 


20-57 


[ -- z 


12-47 


11-12 


2-22 


2-30 


. . 


0-30 


3-52 


1 4-531 


2-64 


0-45 


, , 


5-74 
2-28 


3-51 



100.00 



10000 



2. The Wairakau Series. 
(a.) Structure and Distribution. 

The Wairakau Series consists mainly of andesitic breccias, with which are associated 
inconstant tuft-beds, lava-Hows, and dyke rocks, and rarely carbonaceous sandstones. 

The series attains its maxinmm development on the western side of Whangaroa Harbour 
and on the coast near the heads, where it has a thickness in places of 600 ft. or 700 ft. Thence 
it extends — never reaching further north within the subdivision than the latitude of False 
Head — to the western boundary of the subdivision, forming an elevated tableland with an 
average height of about 900 ft., which is terminated to the westward by the bold bluff of 
Akaterere (1,239 ft. above sea-level). West of .\katerpre the Wairakau rocks appear to have 
been largely removed by denudation. In addition to this main block, which covers about 
fifteen square miles, there is a smaller area of five and a quarter square miles in the country 
drained by the headwaters of the Towai, Tauranga, Mahinepua, and Wainui creeks ; another 
of less than one square mile at South Whangaroa Head ; and several isolated patches, of 
which Peach Island and the hills of Orotere, Taratara, and St. Paul'sJ are the most conspicuous. 

Somewhat interesting are several occurrences of what is apparently the same breccia in 
very close relationship to the flow rocks of the Kerikeri Series. Localities in which the two 
series are found in contact are — the high land to the east of the Inuraia Creek ; the upper 
part of Maria Creek ; Oteroa Creek, near the boundary of the subdivision ; the Kerikeri 
River, about 10 chains below the mouth of Billings Creek, and for some distance down stream, 
and again about half a mile from the eastern boundary of the subdivision ; the head of 
Puruwharawhara Creek ; the Puketotara River, about half a mile below the gum-store, and 
thence down stream at intervals for nearly a mile. 

The tuffs appear to be developed in the basal part of the series, and are very local. They 
suddenly appear in a section, thicken to 10 ft. or 20 ft., and as suddenly die out again. They 
occur very noticeably at the eastern end of Taupo Bay, and thence as far along the coast as 
the " Hole in the Wall," at the western point of Ranfurly Bay, and near the base of St. Peter's. 
The tuffs are also found less conspicuously at Shark Island (Plate JX), and at the south head 
of Whangaroa Harbour. It is possible, as explained in Chapter IV, page 51, that a consider- 
able thickness of greenish tuffs developed near Whangaroa and Totara North belongs to the 
Wairakau Series. 



* In thia analysis no se])arate determination of ferrous oxide was made. 
J Not shown on geological map owing to the smallneas of the patch. 

5 — Whangaroa. 



t By difference. 



66 

The carbonaceous sandstones outcrop in Foley Creek, a branch of Bell Creek, where the 
plant-remains are numerous enough to form small coaly partings. Similar carbonaceous 
sandstones containing coaly partings arc found also in Tauranga Creek, in Oteroa Creek near 
the boundary of the subdivision, and in the middle pait of Rimu Creek. Possibly similar 
to the above are the brown carbonaceous sandstones frequently outcropping on the gum-land 
in the south-west corner of the Whangaroa Survey District. 

Lava-flows are of more common occurrence than dykes, being very abundant in Wairakau 
Creek above its junction with the Otui. They are also found at the eastern end of Taupo Bay, 
near the north head of WTiangaroa Harbour, at the base of the " Bride Cake," in Otui Creek, 
in the lower part of Wairakau Creek, near the mouth of Waihi Creek, on Peach Island, and 
near the head of Mangataraire Creek.* Dykes are seen at the head of Bell Creek and in 
the lower part of the Wairakau, cutting through breccias of Wairakau age. Intruding beds 
of the Kaeo Series, dykes again occur on the Kaeo-Mangonui Road in the cutting leading up 
from Kahoe Creek to the higher land, and on the Totara North Road within a few yards of 
the Kahoe Bridge. There is also a somewhat doubtful occurrence of a breccia dyke cutting 
through Kaeo rocks on the shore of Waitapu Bay. 

(b.) Petrology. 

The breccias, lavas, dyke rocks, and tufEs are all andesitic in character. The following 
types of andesite are identifiable : Augite-andesite, hypersthene-andesite, augite-hypersthene- 
andesite, andesite very poor in ferro-magnesian minerals, oli\ane-andesite, and hornblende- 
andesite. 

The breccias are generally coarse. Ordinarily the contained fragments vary from small 
pebbles to boulders about 1 ft. in maximum diameter, but are in some places even larger. 
Besides the igneous rocks, boulders and pebbles of sedimentary rocks occur in places in the 
basal part of the breccias, especially at False Head. Nearly all the fragments are well rounded. 
In hand- specimens they are generally black or dark grey in colour with porphyritic crystals, 
of which the commonest are plagioclase and augite. They are often vesicular, and the ground- 
mass usually appears crypto-crystalline and occasionally glassy. 

The lava-flows and dykes are usually compact and generally fine-grained rocks of blackish 
or dark-grey colour. 

The breccia band occurring on the shore of Waitapu Bay is so decomposed that the identity 
of its contained fragments with those of the Wairakau breccias is doubtful. The tuSs con- 
sist of a whitish, gritty matrix, through which are scattered lapilli of black andesitic rock. 
In some places they enclose plant-remains, from which Hector and McKay have determined 
the age of the rocks. 

The rarer carbonaceous sandstones are generally fine-grained rocks of greenish colour, 
weathering brown. As already remarked, they contain in places coaly partings — none suflfi- 
ciently large to be called a coal-seam. The fallowing is an analysis of a sample of lignite from 
Tauranga Creek : — 

Fixed carbon .. .. .. .. .. .. 23-85 

Volatile hydrocarbons . . . . . . . . . . 34-31 

Water .. .. .'. .. .. .. .. 18-99 

Ash .. .. .. .. .. .. .. 22-85 



100-00 
Under the microscope the groundmass of the rocks constituting the breccias, flows, and 
dykes is most commonly of the " andesitic " or hyalopilitic type — i.e., it consists of very 

* In Whangaroa Survey District. 



PLATE XTIT. 







Micro-photographs of Kaeo, Wairakau, and Kerikeri Rocks. 

1. Tuff, Kaeo Series, road near Whangaroa. 

2. I'yroxi'ne-andesite, Wairakau Series, near False Head. 

3. Hornblende-andesite, Wairakau Series, St. Paul's Hill. 

4. Dolerite, Kerikeri Series, Okaihau side of Lake Omapere. Nicols crossed. 

AH magnified about 30 diamft(as. 
MicTO-photo. hij Dr. P. Marshall."} 

Bulhtin No. «.] 



[Face -p. 66. 



67 

small feldspar laths and pyroxene crystals embedded in a residual glassy matrix. Another 
common type shows a groundmass which is mainly an isotropic glass crowded with trichites, 
the only anisotropic constituents being minute granules, apparently of feldspar and augite. 

Very common phenocr\-sts are feldspars, ranging from albite (rare) to anorthite, the 
usual species being andesine and labradorite. Equally, or in some, cases more, abundant are 
pale-brown augite crystals. Hypersthene is of frequent occurrence, though never so plentiful 
as augite. HornV)lende and olivine are sometimes found. Amongst accessory minerals, 
magnetite and, in a lesser degree, apatite are the most frequent (Plate XIII, Nos. 2 and 5). 
An interesting variety of andesite was obtained in Okura Creek (which enters Whangaroa 
Harbour near Totara North), from a boulder 5 ft. or 6 ft. in diameter, and probably, therefore, 
derived from a lava-flow. The rock shows a considerable amount of isotropic groundmass. 
There are fairly abundant phenocrysts of feldspar (chiefly andesine), with many inclusions, 
some of which are fluid and arranged in zonary fashion. There is also a large quantity of 
strongly pleochroic brown hornblende and a smaller amount of paler augite and h}^ersthene. 
The augite crvstals are much the smallest in size of the ferro-magnesian minerals. 

A somewhat exceptional t\'pe of hornblende-andesite occurs as flows or dykes in Road 
Creek (a branch of the Upokorau). The rock is even-grained, with hardly any glassy base. 
It is largely made up of very numerous crystals of hornblende and intermediate feldspar, sur- 
rounded by a finely crystalline mosaic of feldspars and ferro-magncsians too small to identify. 
Round their margins the hornblendes show alteration, which has resulted in the bleaching 
of the outer part of the crystals with the formation of irregular streaks of separated iron- 
ore. 

In the upper part of Mahinepua Cn-ek occurs an andesitic rock with two generations 
of augite, the younger augites being moulded on the feldspars. In this respect this rock 
resembles the Kerikeri dolerites ; it nevertheless appears to belong to the Wairakau breccias, 
close to which it occurs. 

The petrological characters of the patches of breccia found in contact with the Kerikeri 
Series are usually not exceptional. The breccia from the high land east of the Inumia Creek 
is rather richer in pvroxenes than the normal Wairakau rocks. From Maria Creek a very 
compact and fine-grained breccia resembling the Parnell grits, near Auckland, was obtained. 
Small inclusions of argillite are found occasionally in the dyke rocks of Wairakau Creek 
and in boulders of breccia in Lane Creek. 

The following common t}'p<'S have been recognised in the localities given : — 
Augite-andesite — Peach Island. 
Hypersthene-andesite — False Head. 

Augite-andesite with some hypersthene — St. Paul's, " Bride Cake," " Haystack," 
east side of Akaterere, Orotere, Otui Creek (with small amygdules of chalcedonic 
quartz), and many other locahtics. 
Andesite very poor in ferro-magnesian minerals — St. Paul's. 
Olivine-andesite — Otui Creek about half a mile above junction with Wairakau. 
Hornblende-andesite — St. Paul's, Akaterere, Wairakau Creek near Campbell's 
shanty, Bell Creek, and Waionepu Creek. 
The chemical composition of the breccias is fairly indicated by the following analysis of 
a general sample from the top of St. Paul's (No. 1 below). In the second and third columns 
are placed analyses of a typical hyalopilitic hypersthene-andesite from the Beeson's Island 
Series,* and of a general sample from' the breccia occurring at Coal Point, near the North 
Cape. It will be seen that the rocks from these widely separated localities show a striking 
similarity in composition. 



* Bull. Xo. 4 (\ew Scries), N.Z.G..S.. 1907. ]>. 82. 
5'— Whangaroa 



68 





No. 1. 


No. 2. 


No. 3. 


Silica (SiOj) .. 


. 58-20 


57-68 


59-20 


Alumina (AI2O3) 


. 18-35 


18-84 


18-03 


Ferric oxide (FcgOg) 


1-44 


4-96 


1-40 


Ferrous oxide (FeO) 


3-46 


1-44 


2-88 


Manganous oxide (MnO) . . 


0-35 


0-21 


0-40 


Lime (CaO) 


6-20 


6-05 


7-03 


Magnesia (MgO) 


3-49 


400 


2-51 


Potash (K 2 0) .. 


2-96 


2-15 


2-28 


Soda (Na^O) . . 


2-63 


2-16 


2-93 


Titanium-dioxide (TiO 2).. 


0-87 


0-82 


1-26 


Carbonic anhydride (CO 2) 


Nil 


0-75 


Nil. 


Water and organic matter 


205 


0-90 


2-08 



10000 



99-96 



100-00 



(c.) Secondary Siliceous Deposits. 

Secondary siliceous deposits of no great importance are found in the breccias at various 
places near Whangaroa Harbour. The most noteworthy of these occurs on Wairakau Creek, 
about a quarter of a mile above its junction with Otui Creek, where deposits of yellowish- 
green banded silica occur abundantly between the boulders of the breccia and in the joints 
of an associated lava-flow. Silicified tree-trunks or wood opal, in which the original structure 
is to some extent preserved, are of fairly frequent occurrence in the cliffs of breccia near St. 
Peter's and (lying loose, but probably derived from the breccia) in the middle part of the 
Tauranga Valley. The wood opal from the first locality is semi-transparent, and of a rich 
reddish-brown hue. It has been considered by jewellers to be of some value for the manu- 
facture of cheaper articles of jewellery. 

In the microscopic sections which were made of the opal from St. Peter's it was found 
that only the structure of the woody portion of the trunk is preserved. Transverse and 
longitudinal sections showed resin-canals of the usual character very distinctly. The presence 
of bordered pits and other details of structure in the elements of the wood could not be satis- 
factorily made out, but from the small size and regular arrangement of these elements in 
transverse section, and from the indications of their pointed closed ends in longitudinal section, 
they appear to resemble closely the tracheids of a modern conifer. 

(d.) Correlation and Age. 
Wairakau rocks are seen to overlie the Waipapa Series unconformably near False Head, 
and the Kaeo Series at Peach Island, near the western point of Ranfurly Bay, and at the 
northern end of Pumanawa Bay. McKay* correlates the pyroclastics of the Wairakau Series 
with the breccias occurring near the North Cape and with the Manukau breccias which are 
developed near Auckland. Similar breccia-beds are also found near Whangarei, Hokianga, 
and in the Coromandel Peninsula. The only palseontological evidence as yet available for 
fixing the age of the Wairakau Series is cited by McKay, who considers certain fern-impressions 
(found in the tuffs) to be identical with those occurring in similar beds in the North Cape 
district. The North Cape beds are, on other palseontological grounds, correlated with the 
Manukau breccias, as to the Miocene age of which there is general agreement. 



* " On the Geology of Hokianga and Mongonui Counties, Northern Auckland," Rep. G.S., 1892-3, No. 22, 
1894. p. 82. 



69 

Petrologically the Wairakau Series shows, so far as can be seen, a fairly close resemblance 
to the rocks of the Manukau breccias.* It should be noted, however, that hypersthene is 
not universally present, whereas Marshall found it in all his sections of Manukau breccias. 
A comparison with the petrology of the Beeson's Island Series, as described by Sollasf and 
Fraser and Adams,| shows that the Wairakau Series has so far been found wanting in dacites, 
which are, however, apparently of rather rare occurrence in the Beeson's Island Series. Per- 
haps a more important difference lies in the fact that the dominant ferro-magnesian mineral 
is hypersthene in the Beeson's Island Series, while augite predominates in the Wairakau Series. 
Making full allowance for these difierences, there is nevertheless a strong similarity between 
the rocks of the two series. 

(e.) Conditions and Foci of Eruption. 

The abundance of fragmental volcanic rocks in the series points to the occurrence of par- 
oxysmal eruptions during Wairakau times. The stratification shown even by the coarsest 
beds and the absence of plant-remains in situ indicate that the rocks were probably deposited 
in shallow water.§ By the agency of the water, the larger fragments, whose angularity had 
already been subdued by friction during the eruptions, were rounded. 

As the Wairakau rocks are traced from their niain exposure on the west of Whangaroa 
Harbour towards the south and cast, their thickness is found to diminish from 500 ft. or more 
near the mouth of the Wairakau Stream, to about 100 ft. on St. Paul's, Taratara, and Orotere ; 
and at the same time their base is seen to rise from sea-level to 400 ft. and more. It is to 
be noted, moreover, that this decrease in thickness and elevation of the base of the series 
takes place ven,' suddenly at St. Paul's, suggesting that the upper part of the harbour lies 
on a line of weakness along which faulting has taken place since the deposition of the Wairakau 
rocks (see Chapter II, page 23). The thinning-out of the series to the south and east may 
therefore be due mainly to the more rapid removal by denudation of the portions elevated by this 
faulting. Nevertheless, the greater size of the boulders in the northern exposures, and more 
particularly the presence of interstratified lava-flows, show that probably the main volcanic 
activity was in this neighbourhood. There is evidence of one vent near the head of Rukuwai 
Creek, where the breccia-beds are steeply inclined and broken through by dykes ; and, as 
already mentioned (Chapter III, page 27), it is possible that some of the higher breccia 
knobs, such as Tehe o Riri, Akaterere, Patukohatu, and Orotere, are necks of old cones. 



3. The Kerikeri Series. 
(a.) Structure and Distribution. 

The Kerikeri Series consists of a succession of lava-flows, covering, with an almost con- 
tinuous sheet, an area of about 79^ square miles lying mainly along the eastern border of the 
subdivision, but found also in small patches on hill-tops and ridges further west and on Flat 
Island and Motuekaiti on the sea-coast. Directly underlying the flow rocks in several places 
are thin local beds of peat, lignite, and carbonaceous sandstones and shales, which will be 
later described. 

* Mulgan, " On the Volcanic Grits and A.sh-bcds in the Waitemata Series," Trans., vol. xxxiv, 1901, p. 429 ; 
Fox, " The Volcanic Bed.s of the Waitemata Series," ib., p. 492 ; .Marshall, " Geology of Centre and North 
of North Island," Trans., vol. xl, 1907, p. 96. 

t " The Rocks of Cape Colville Peninsula " (2 vols.), 1905. 

1 Bull. No 4 (New Series), N.Z.G.S., 1907, p. 80, &c. 

§ The breccias near the North C'ape and those of the Beeson's Island Series of Coromandel (Bull. No. 4 
(New Series), N.Z.G.S., 1907, p. 7fi) contain thin coal-seams, which are evidence of the recurrence of terrestrial 
or very shallow-water conditions. 



70 

(b.) Petroloyy. 

The volcanic rocks of the Kerikeri Series are mainly dolerites, but unimportant flows 
of andesite appear to be interbedded with them at the heads of Billings and Manginangina 
creeks, in two places in the Kerikeri River, at the head of the WTiakanekeneke River, and 
in the high land overlooking the Waipekekahau Stream. Andesite-flows also form the cap 
of Takapuwahia Hill. In the field the dolerites are generally compact, show few steam[cavities, 
and are mdely jointed. Good hexagonal jointing is seen in Oteroa Stream, on Flat Island, 
on Motuekaiti, and at the source of the Waiarewau Stream. 

The Kerikeri rocks are remarkably constant both in megascopic and microscopic characters. 
In hand-specimens the dolerites are generally black, but occasionally grev, finely crj'stalhne, 
close-grained rocks, with a variable number of phenocrysts of glassy feldspar, and frequently 
olivine. Vapour cavities sometimes filled with spherulitic limonite occur, but are never very 
abundant. 

Under the microscope the prevalent type is an evenly crystalhne rock, made up chiefly 
of a network of feldspar laths (mainly labradorite and anorthite) embedded in a groundmass 
which is composed almost exclusively of light-brown augite. The augite in places assumes 
a banded structure, due to decomposition processes. Olivine occurs frequently, but was 
found abundantly only in the outcrops of Kerikeri* rock, occurring in the upper part of the 
Manga tawai Creek (see also Chapter IV, page 58). H}'persthene is sometimes, and magnetite 
always, present. 

Specimens of this type of dolerite have been obtained from everj- locality in which the 
flow rocks of the Kerikeri Series are developed, with the exception of some of the isolated 
patches on hill-tops (Plate XIII, No. 4). 

Another type of dolerite is one in which the rock is made up in the main of lath-shaped 
feldspars (labradorite and anorthite), with a few larger phenocrysts of augite, feldspar, and 
occasionally olivine. Entangled in these laths and phenocrysts is a varying but not very 
great quantity of very small crystals and granules of feldspar and pale-brown augite. Magne- 
tite is usually more plentiful in this t^'pe of dolerite than in the one first described (Plate XIV, 
No. 1). Olivine is abimdant in a rock of this type obtained from the slope leading down to the 
Waitangi River from Waimate North. 

Occasionally, by the reduction in the size of the feldspar laths and the almost complete 
disappearance of the larger crystals, the rock is reduced to a fine mosaic of feldspar and 
augite. 

A distinct variety was obtained from Whataipu Creek. This rock is found, under the 
microscope, to be almost entirely made up of labradorite and anorthite laths. One or two 
porphyritic crystals of labradorite occur, but, save for a few minute almost colourless granules 
of augite, ferro-magnesian minerals seem to be absent. Magnetite is very abundant, in some 
cases filling up the feldspars and obscuring their optical properties. 

Inclusions of quartz sm'rounded by zones of roughly radiating augite crystals are abundant 
in a rock from the Puketotara River, near the eastern boundary of the subdivision (Plate XIV, 
No. 2). 

On the ridges west of the Pupuke River, near the head of Mangamuta Creek, occur huge 
boulders of igneous rock 10 ft. or more in height. Equally large boulders are even more 
abundant on Takapuwahia Hill, at the head of the Mangakino. In microscopic characters 
these boulders resemble one another, and differ from all others in the subdivision. They are 
augite-andesites with a considerable amount of glassy base, and are characterized by the 
abmidance and length of the feldspar laths, which seem to form a lattice -work. 

The andesite forming the large boulders which occur in the upper Pupuke River, near the 
mouth of Paripawa Creek, is indistinguishable imder the microscope from the andesites of 



PLATE XIV. 







MiCRO-PHOTOfiRAI'HS OF KkRIKERI AND LaTER VoLCANICS. 

1. Cranulitic iloleiite, Kei ikeri Series, Maungaemiemi Hill. 

2. Doleiite with quartz inclusions, Kerikeri Series, Puketotara River. 

3. Rhyoiite. Piitahi Hill. 

4. liasalt in<-lining to an andesite, older portion of later basic volcanics, Tarahi Hill 

All magnified about 30 diameters. 
Mirro-p/iofo. hi/ Dr. P. MarxhaU.'\ 

Bulletin iVo. S.] 



[Pace p. 70. 



71 

St. Paul's. It is probable that, though their microscopic characters are not quite the same, 
these boulders belong to the same flow as that on Takapuwahia, 
Three analyses of Kerikeri flow rocks are subjoined : — 





No. 1. 


No. 2. 


No. 3. 


Silica (SiOa) . . 


. 53-57 


50-05 


46-67 


Alumina (AljOy) 


. 16-96 


17-53 


22-36 


Ferric oxide (Fo^Oj) 


2-08 


4-40 


1-44 


Ferrous oxide (FeO) 


7-29 


4-82 


7-70 


Manganous oxide (MnO) . . 


0-35 


0-30 


0-32 


Lime (CaO) 


9-55 


805 


10-27 


Magnesia (MgO) 


3-70 


646 


2-90 


Potash (K2O) . . 


2-03 


1-67 


1-50 


Soda (Na^O) . . 


2-15 


2-47 


1-87 


Titanium dioxide (TiO^).. 


1-15 


1-42 


1-19 


Carbonic anhydride (COj) 


Nil 


Nil 


005 


Water and organic matter 


1-17 


2-83 


3-73 



10000 10000 100-00 

No. 1 is the compact variety of dolerite forming the upper flow of lava on Flat Island. 
No. 2 is the vesicular variety of dolerite forming the lower flow of lava on Flat Island. 
No. 3 is a dolerite from the slope leading down to the Waitangi River, opposite Atkinson's 
store, Waimate North. 

(c.) Loctd Aqueous Deposits. 

Underlying the flow rocks included in this series are found, in various places, local accunm- 
lations of lignite, peat, and carbonaceous sandstones and shales. These may be well seen at the 
head of Landslip Creek, a branch of the Waiarewau Creek, where the deposits consist of an 
earthy peat containing the remains of branches and roots of trees. About a mile and a 
quarter south of this locality, at Mr. Copeland's house, the same deposits arc represented by 
the Pungaere kerosene-shales. Beds probably of similar origin occur on the right bank of 
the Upokorau, in the neighbourhood of Coal Creek. These and the Pungaere shales will be 
more fully described in Chapiter VI. 

Outcrops of a similar nature too small to be indicated on the map occur at the head- 
waters of the Waipekekahau Creek (a branch of the Whakanekenekc), a lignite from which 
analyses as follows : — 

Fixed carbon . . . . . . . . . . 22-20 

Volatile hydrocarbons . . . . . . . . 35-51 

Water .. .. .. .. .. .. 35-67 

Ash .. .. .. 6-62 



100-00 

There is little doubt that the Pungaere and Landslip Creek exposures form part of an 
old lake-basin or extensive swamp on the peneplain of Kaeo rocks, which was covered by the 
flows of Kerikeri lava. 

Carbonaceous mudstones occurring at the head of the Arotoro and Waitemanu creeks, 
and containing small lenses of lignite, may possibly belong to the deposits under dis- 
cussion, and unconformably overlie the Kaeo rocks of the neighbourhood. Clear evidence 
on this point could not be obtained, and the rocks have therefore been classed with the Kaeo 
Series. 



72 

(d.) Correlation and Age. . 

Rocks resembling the Kerikeri flows have not yet been fully described from other parts 
of New Zealand. Marshall* describes the predominant rock from Pirongia and Karioi, south 
of Auckland, and considers that it " is, perhaps, best called a dolerite." The Kerikeri Series 
was classed by McKayf as Tertiary. MarshallJ reports that at Kerikeri the series rests on 
Miocene rocks. 

In a number of localities aheady enumerated (page 65) patches of breccia of Wairakau 
type occur, in most cases, but not always, apparently surrounded and covered by flows of 
Kerikeri rocks, though the precise relationship of the two series is nowhere clearly seen. 
The probability, however, is that the Kerikeri rocks are unconformably younger than the 
Wairakau. 

It also seems possible that there is no decided break in time between the rocks of the 
Kerikeri Series and those of the later basic volcanics seen near Lake Omapere. In the section 
on the latter rocks reasons will be given for supposing that volcanic activity has been more or 
less continuous in the district from the beginning of Kerikeri times. 

(e.) Conditions and Foci of Eruption. 

The area covered by the Kerikeri flows at the present day has aheady been given, but, 
judging from the occurrence of outhers of lava of the Kerikeri type on hills further to the 
west — such as Maungaemiemi, Takapuwahia,§ Rotomanoao, and Te Rangi (a hill lying north- 
west of Takapuwahia and about three quarters of a mile outside the subdivision boundary) — 
there is little doubt that the lava-sheet originally spread much further to the west. Such 
hills as Manginangina (1,247 ft.), Huia (1,263 ft.), Maungaemiemi (1,222 ft.), Te Rangi (1,226 ft.), 
and trigonometrical stations H (1,177 ft.) and A (1,195 ft.) (in the Omapere Survey District), 
are elevated somewhat above the general level of the tableland, and may conceivably be the 
stumps of the volcanoes from which the lava issued. It is, however, quite possible that the 
flows are in the main due to fissure eruptions, like those by which the Snake River plateau 
in Oregon was formed, and that the higher hills are simply the results of difierential 
erosion. 

The small occurrence of lava on Flat Island and Motuekaiti probably never formed part 
of the main sheet, as it is separated by a considerable gap from the other flow rocks of the 
Kerikeri Series, nor is there evidence of its ever having been continuous with them. It seems 
Ukely that Flat Island and Motuekaiti are the remains of a small independent lava-sheet 
w^hich was probably contemporaneous with the Kerikeri flow rocks, and may owe its inferior 
altitude to faulting. 

4. Acidic Igneous Rooks. 
(a.) Structure and Distribution. 

Acidic igneous rocks occur in only two localities within the subdivision — namely, near 
Pungaere, at the head of the Waiarewau Stream, and on the hill of Putahi and'the slopes 
descending therefrom on the south side of Lake Omapere. 

Numerous blocks of obsidian, ranging in size from small pebbles to boulders a foot in 
diameter, are found scattered over the tableland of Kerikeri lavas one to two miles north of 
the Pimgaere Settlement. Somewhat larger blocks are found in the bed of Waiarewau Creek, 
whither they have probably descended from the tableland in slips. The two areas|| over 



* " Geology of Centre and North of North Island," Trans., vol. xl, 1907, p. 96. 

t Rep. G.S., 1892-3, No. 22, 1894, sketch-map facing p. 80. 

j Loc. cit., p. 88. 

§ The Takapuwahia lava is, however, a distinct type (see p. 70). 

II Indicated on the geological map. 



73 

which these fragments are found cover, in all, less than half a square mile. All the fragments 
show a thoroughly rounded and weathered surface. Careful search failed to reveal any volcanic 
vent whence these fragments of obsidian might have been derived. The nearest occurrence 
of acidic volcanic rocks is at Putahi, from which the Pungaere area is separated by about 
.welve miles of country on which no obsidian has been found. The explanation that the 
fragments of this rock were brought by the Maoris of bygone days (obsidian chips were used 
as flesh-knives*) seems untenable, for the following reasons : The blocks are not gathered 
into heaps, but are scattered broadcast ; they are very numerous, and seldom, if ever, show 
any signs of the chipping that would be expected if they had been made use of by the Maoris : 
moreover, the locality shows no signs of former Maori occupation. 

Though the hummock-shaped hill of Putahi (Plate IV) has no crater, its outline is possibly 
little altered since its formation, as it is generally recognised that in the case of the viscid 
acid lavas such bubble-shaped excrescences are frequently formed as the result of the final 
eruption of lava.f Numerous vertical or very steeply inclined pipe-like holes were probably 
steam-vents (see Chapter III, page 27). The area covered by Putahi Hill and the rhyolite- 
flows from it is approximately one square mile. 



(ft.) Petrology. 

The acid igneous rocks consist of obsidian and rhyolite. In hand-specimens the obsidian 
is a typical black glass without structure of any sort. Under the microscope some specimens 
are seen to be an almost perfect volcanic glass, through which are scattered a very few fine 
microlites of green hornblende and apparently acidic plagioclase. Other specimens show 
more abundant microlites. Obsidian occurs only as scattered fragments near Pungaere. 

The acid rocks from Putahi Hill are megascopically at once identified as brownish-white 
somewhat decomposed rhyolites, in which quartz forms the only recognisable phenocrysts. 
Under the microscope the rhyolite has a micro-crystalline groundmass made up of exceedingly 
minute grains of quartz and feldspar, together with a considerable amount of residual glass, 
which appears to contain a good deal of some iron-bearing mineral, judging by the results 
of analysis and by the light brown to which the rhyolite weathers. In the groundmass are 
embedded a few large phenocrysts of glassy quartz and orthoclase. Ferro-magnesian minerals 
seem to be almost entirely wanting, except for occasional small crystals of hornblende nmch 
stained with limonite (Plate XV, No. 3). 

The following are analyses of typical acid rocks. No. 1 is an ob.sidian from a large block 
in the Waiarewau Creek, and No. 2 is a rhvolite from Putahi Hill. 



Silica (SiOa) . . 
Alumina (AI2O3) 
Ferric o.xide (FejOj) 
Lime (CaO) . . 
Magnesia (MgO) 
Potash (K2O) 
Soda (Na^O) . . 
Titanium-dioxide (TiOj) 
Carbonic anhydride (CO 2) 
Water and organic matter 



No. 1. 


No. 2. 


. . 7.3-37 


72-50 


9-69 


10-67 


4-48 


4-16 


114 


1-58 


0-37 


0-.52 


5-91 


4-72 


4-38 


3-38 


008 


007 


Nil 


Nil. 


0-58 


2-40 


10000 


100-00 



♦ See, for example, " Traditions and Superstitions of the New-Zealanders," by Edward Shortland 1856 
p. 148. 

•j- Judd, " Volcanoes," 6th ed., 1903, p. 160. 



74 

5. Latkr Basic Volcanics. 
(«.) Structure and Distribution. 

The later basic volcanics cover an area of about seventeen square miles in the south- 
eastern part of the subdivision, forming the northern corner of a considerable area of such 
rocks which exists to the east and south. Difficulty is experienced in attempting to fix 
definitely the boundary between these rocks and those of the Kerikeri Series ; in fact, both 
in the field and ruider the microscope the rocks are found to grade into one another. The 
writers consider it quite possible that when observations have been extended over a wider 
area evidence will be obtained that vulcanism was intermittently active from Miocene to 
Pleistocene or Recent times, and that there is thus no very prolonged and definite break 
between the Kerikeri and later basic volcanics. 

These latest volcanic accumulations attract more popular attention than the much more 
extensive ones of Kerikeri times, owing to the comparative freshness of most of the puys 
and of the lava which flowed from them, and on account of the more fertile land which is 
formed by the decomposition of the lava. 

More or less denuded volcanic cones of the later basic volcanics form the high land which 
overlooks Lake Omapere on the east and south-east. Flows from these cones have considerably 
altered the topography of this area, filling up stream- valleys, and in particular damming up the 
headwaters of the Waitangi River to form Lake Omapere (page 33). 

The only cone at all perfectly preserved is that of Te Ahuahu or Pukenui, which rises to 
a height of 1,240 ft. above sea-level, and has a rather small crater, broken down on the western 
side. More dissected, but still recognisable, cones are those of Maungakawakawa, Waimimiti, 
and Kaikohe. The high land surrounding the basin-shaped hollow at the head of Pungatere 
Stream and the rounded hill of Tarahi probably represent the much-denuded remains of 
larger and older cones belonging to these later basic volcanics. 

(b.) Petrology. 

The later basic igneous rocks are basalts, inclining in places to andesites. In the field 
they may usually be distinguished from the older (Kerikeri) effusives by their fresher appearance, 
their lighter colour, and the greater abundance of vapour cavities. 

Mecascopically they are dark-coloured, generally fine-grained, vesicular rocks with pheno- 
crysts of augite, olivine, and feldspar, the latter sometimes large. 

Under the microscope the groundmass of the rock is seen to be made up of lath-shaped 
feldspars (labradorite and anorthite), roughly arranged in flow-lines, together with numerous 
granules of pale-brown augite. Embedded in this matrix are a few larger phenocrysts of 
feldspar, rare large augites, and small idiomorphic olivine crystals, the latter usually stained 
brown in the interior, but having a clear margin. Magnetite is of general occurrence, though 
not very abundant (Plate XV, No. 1). 

The slightly older lavas of this series, such as that occurring on Tarahi, are of a 
different type. They display hyalopilitic structure, feldspar laths arranged along flow-lines 
being embedded in a glassy groundmass. There are numerous crystals of augite of two widety 
different sizes, nearly all being much stained with limonite ; and a few corroded phenocrysts 
of andesine, labradorite, and olivine. Magnetite is very abundant. Attention may be called 
to the absence of multiple twinning in the feldspars in rocks of this type (Plate XIV, No. 4). 

Powdered samples of the later basic volcanics from various localities were treated with 
hydrochloric acid, but no crystals of common salt could be detected on evaporation of the 
solution, although abundant crystals were obtained, by exactly the same treatment, from 
a phonolite from the neighbourhood of Dunedin. The later basic volcanics of the Whangaroa 
Subdivision have not so far, therefore, been found to contain nepheline, and therefore are 
not basanites. Marshall has, however, found basanites amongst similar rocks from the Bay 



PLATE XV 








m 






IbJI 



MlCl!O-l'HOT0f:i(.\I>IIS OK I.ATKH l{.\SIC Vor.CAXICS AXU lONKOLTS IJocKS OK DoUllTKUI> AoE 

1. Basalt, later basic volianics. Te Ahuahu Hill. Niools crossed. 

2. Gabbio, post-Waipapa and probably post-Kaco. north of Frear Bay. Nicols crossed. 

:'.. .Mtered aiidcsite, younger than rocks of which .\o. 2 is an example, dyke between Camp Bay and Frear 

1. Altered pynxjastic, .same age as No. :5, about half a mile west of Karaui. Nicols cros.sed. 

All magnified about 30 diameters. 
Mur„-pl,olo. h,j Dr. I>. Mar.<han.] 

Bulletin No. «.] (^//^..^ ^ ^j^ 



75 





. 50-89 




17-75 




2-32 




7-20 




. 0-21 




7-70 




3-30 




2-43 




3-83 




1-97 




005 




2-35 



of Islands district and also in the volcanic rocks of the Auckland isthmus,* with which it 
seems likely that the rocks underrconsideration are^ contemporaneous. 

An analysis of the rock forming one of the lava-flows from Te Ahualiu Hill is as follows :- 

Silica (SiOj) 

Alumina (AI2O3) 

Ferric oxide (FcoOj) 

Ferrous oxide (FeO). . 

Manganous oxide (MnO) 

Lime (CaO) 

Magnesia (MgO) 

Potash (KjO) 

Soda (Na.O) 

Titanium -dioxide (TiOj) 

Carbonic anhydride (CO 2) 

Water and organic matter 

10000 
6. Igneous Rocks of Doubtful Age. 
At several places in the subdivision rocks occur to which no definite age can be given. 
These may be considered under the following heads : — 
(a.) Igneous rocks either Wairakau or Kerikeri in age. 
(b.) Igneous rocks post-Waipapa and probably post-Kaeo in age. 
(c.) Igneous rocks younger than those of the preceding section. 

(a.) lyneous Rocks either Wairakau or Kerikeri in Age. 

Here may be mentioned a number of rocks, more especially intrusives, occurring near 
the point of contact of the Wairakau and Kerikeri series, that cannot be definitely assigned 
to one series or the other. 

Dykes are well shown in Fred, Waiarewau, Landslip, Rukuwai, and Waionepu creeks. 
WTiat is apparently a dyke of much-decomposed andesitic rock occurs in the Kaeo River 
about 30 chains above Mr. G. Sievers's house. In the I'pokorau Creek, near its junction 
with Road Creek, there appears the most extensive exposure of dyke rocks observed in the 
subdivision. The large dyke which occupies the spur between the I'pokorau and Waiare- 
wau creeks is essentially a fine-grained doleritic rock, probably connected with the Keri- 
keri flows ; it formerly contained phenocrysts, but these have all been completely 
decomposed. A specimen obtained close to this outcrop, and apparently belonging to the 
same dyke, is a typical Wairakau andesite poor in ferro-magnesian minerals. All these dykes 
cut Kaeo rocks. 

In Fred Creek a hornblende-andesite dyke occurs close to, and perhaps penetrating, a 
decomposed breccia. The hornblendes are surrounded by resorption borders, and are greatly 
altered. Similar andesites occur as dykes in Waionepu and Road creeks. The dyke rocks 
referred to in this paragraph are generally compact, no decomposition being visible even 
in microscope sections. 

In the Takou River, towards the boundary of the subdivision, occur a number of much 
altered hornblende-andosites, both as flow and dyke rocks. In general characters they ap- 
proximate to the Wairakau type. 

A rather exceptional specimen of flow rock from the Takou River shows under the micro- 
scope a doubly refracting groundmass of minute laths {'. feldspar), with a rough spherulitic 
grouping. Through the groundmass are plentifully scattered large crystals of oligoclase 



• " Geology of Centre and North of North Island," Trans., vol. xl, 1907, p. 96. 



76 

and andesine, and perhaps some orthoclase. There also occur large, completely altered crj'stals 
of augite. Pyrite is fairly abundant. The rock is thus distinctly more acid than the normal 
Kerikeri rocks, and would approximate to a dacite. No free quartz was, however, distinguished. 
In the upper waters of Waikoura Creek occurs a considerable mass of highly decomposed 
and somewhat pyritised volcanic rock, apparently andesitic in character. No definite evidence 
as to its relationship to the neighbouring Kaeo Series could be obtained. It may be temporarily 
classed with the rocks just described as occurring on the Takou River. 

(6.) Igneous Rocks Post-Waipafa and probably Post-Kaeo in Age. 
Structure and Distribution. — On the coast north of Whangaroa Heads is found a considerable 
development of basic intrusives in the form of great dykes penetrating the rocks of the Waipapa 
Series. These intrusives frequently occur on the coast-line between Taupo Bay and Mata- 
nohinohi, having largely usurped the place of the Waipapa sedimentaries, and are also found 
in Camp and Taupo creeks and on the slopes of Takitimu Hill. South of Takitimu they are 
not seen, and north of Matanohinohi they are themselves intruded by later igneous rocks. 

Probably belonging to the same phase of igneous activity are the rocks forming the core 
of the Maungaemiemi Ridge from the headwaters of the Pupuke to the top of the Kaikinikini 
Stream, and also occurring at Taupuke Point, in the Papakanui and Waitaruke creeks, and 
in the upper waters of the Whakateterekia. In all these localities, as great dykes, they pene- 
trate, bake, and mineralise Kaeo rocks. 

Petrology. — The rocks under consideration show a considerable variation in petrological 
character, being andesites, diabases, diorites, and gabbros. In hand-specimens they may 
be seen to range in texture from fine-grained to coarsely crystalline. Their colour is almost 
invariably dull green or dark grey. In the finer-grained varieties no individual minerals 
except ferro-magnesians and secondary pyrite can be recognised, while in the more coarsely 
crystalline rocks large plagioclase-feldspars and ferro-magnesian minerals — the latter some- 
times radiately grouped — are readily identified. 

Under the microscope, the andesites, which are the finest-grained of these rocks, show 
a considerable proportion of glassy groundmass, in which occur feldspar laths and pyroxene 
granules. The phenocrysts are of pale-brown augite, and of another pyroxene (possibly 
hypersthene) greenish in colour, the individuals of which are now almost completely 
masked by granules of pyrite and magnetite, or are altered to a fibrous aggregate of calcite 
and chlorite. The feldspars are generally more or less completely crushed, but are appa- 
rently andesine and labradorite. 

The post- Waipapa andesites are found along the coast-line at intervals between Taupo 
Bay and Karaui Point, and again on Cone Rock. They occur either as dykes or flows, but, 
owing to the dislocation which they have undergone, it is sometimes difficult to come to 
definite conclusions as to the original character of the occurrences. 

The diabases are fine-grained rocks found in situ on the Pupuke Copper-field (for example, 
at the end of the Ferguson Company's drive in Morrison Creek), and on the coast-line between 
Taupo Bay and Camp Bay. Under the microscope the rock is seen to be made up of a plexus 
of basic feldspar laths embedded in an opaque groundmass, thus showing .considerable re- 
semblance to the contemporaneous flows of the Waipapa Series. In neither case, however, 
are the rocks sufficiently well preserved to render a detailed comparison possible. Those 
occurring along the coast-line, in addition to ordinary chemical changes due to weathering, 
are very considerably crushed by subsequent movement. It is probable that many of the 
schistose rocks described under the Waipapa Series really belong to this category. 

The diorites are dark-green crystalline rocks, occurring in considerable quantity at the 
northern end of Frear Bay, and almost everywhere are much altered. Under the microscope 
they are seen to be made up of altered ferro-magnesian minerals and acid feldspars. The 



77 

feldspars seem to be mainly oligoclase and andesine, but there appears to be some orthoclase. 
The ferro-magnesian minerals are now altered largely to chlorite and calcite, and are therefore 
not easily identified, but both hornblende and augite seem to be represented. The rock appears 
to show ophitic structure in places. In some ways it resembles a syenite, but, owing to the 
large amount of secondary calcite and the abundant ferro-magnesian minerals, it hardly belongs 
to this class. 

The gabbros are found on the Whakateterekia River about half a mile above Mr. Foley's 
house, in a band about 3 chains wide ; in Papakanui and Waitaruke creeks ; at Taupuke 
Point ; on the coast-line between Taupo Bay and Matanohinohi ; near the heads of the Kai- 
kinikini and most of the other streams which rise in Maungaemiemi Kidge ; and are especially 
well exposed in the Oika, at its head, and again just below the mouth of Morrison Creek. 

Under the microscope the gabbros exhibit hypidiomorphic crystals of augite, some diallage, 
hypersthene, labradorite and anorthite, and rarely olivine (Plate XV, No. 2). 

In the gabbro found in the upper Waihuka Stream the ferro-magnesian minerals are 
entirely chloritised, and the feldspars show the commencement of alteration in the clouding 
of their interior by a multitude of minute, unidentifiable scales. 

At the headwaters of the Oika actual transitions from the basaltic to the gabbroitic types 
are to be seen. 

Although the rock occurring at Taupuke Point is almost certainly connected with the 
great gabbro dyke in Papakanui and Waitaruke creeks, it appears to be a more basic segregation, 
being chiefly made up of diallage and olivine (the latter hardly represented in the Papakanui 
and Waitaruke rocks), with only a minor quantity of basic feldspars. 

On the Pupuke Copper-field there often occurs in close proximity to the cupriferous lodes 
ahighly decomposed rock, possibly of igneous origin, which is locally known as " sei^pentine." 
Several specimens of this " serpentine " were analysed and microsfopically examined. All 
seemed to differ from the finer-grained of the igneous nxks just described, chiefly in their 
more decomposed condition. 

No. 1 is a sample of a diorite from an outcrop north and west of Taupo Bay ; No. 2 is 
" serpentine " from No. 4 drive, Whangaroa Amalgamated Company's claim ; No. 3 is 
" serpentine " from the old drive near the head of Frenchman Creek.* 

Silica (SiOj) . . 
Alumina (AljOj) 
Ferric oxide (FcjOj) 
Ferrous oxide (FeO). ... 
Manganous oxide (MnO) . . 
Lime (CaO) 
Magnesia (MgO) 
Potash (KjO) . . 
Soda (Na^O) 

Titanium-dioxide (TiO j) . . 
Carbonic anhydride (CO,) 
Water and organic matter 

10000 10000 10000 

The high percentage of water and organic matter in No. 3 is due no doubt to the shattered 
and decomposed character of the rock. 

Contact Metamorphic Effect of the Intrusions on the Sedimentary Rocks. — Owing to the 
local fracturing which has taken place since the intrusion of the rocks just described, their 

• See also the analysis in Chapter VI, p. 86. ■\ In these analyses no separate determination of ferrous 

oxide was made. tjBy diflference. 



No. 1. 


No. 2. 


No. 3. 


49-75 


48-05 


43-95 


16-70 


20-19 


22-23 


1-61 
8-06 


- II-8lt 


11-55- 


0-10 


. . 


. , 


11 -.35 


7-90 


4-21 


6-98 


5-40 


4-85 


1-52 
1-62 


2-93t 


2-50] 


0-80 


, , 


, , 


Nil 


, , 


Nil. 


1-51 


3-72 


10-71 



78 



metamorphic effects on the Waipapa and Kaeo rocks have to a certain extent been obscured. 
There can be little doubt, however, that the intrusion of such a large body of molten rock 
must be largely responsible for the changes in mineralogical composition both in the coastal 
exposure and in the Pupuke Copper-field. In this latter place the effect is especially marked 
in the hardening that has been induced in the sedimentary rocks near the line of contact, 
and in the production of the cupriferous veins.* 

(c.) Igneous Rocks younger than those of the Preceding Section. 

Structure and Distribution. — Effusive, p\Toclastic, and intnisive rocks of doubtful age 
occupy a considerable part of the sea-front between Matanohinohi and Tupo Bay. They 
consist of much-altered semi-basic tuffs and breccias, and less altered dykes and flows. Owing 
to the extensive decomposition and alteration which they have undergone, the pyroclastics have 
lost almost all trace of their original arrangement. They seem, however, to have undergone 
local faulting and displacement. Dykes of these rocks penetrate rocks of the Kaeo and Wai- 
papa series and also the post- Waipapa igneous rocks described under heading (b). 

The effusives of this class are found chiefly in the eastern portion of the coastal exposure 
and near the headwaters of Matanehunehu Creek. The pyroclastics replace the lavas west 
of Karaui Point, and then persist — with occasional associated dykes and flows — to about half 
a mile beyond the Sugarloaf. The dyke rocks are found penetrating the pyroclastics and 
also intruding older rocks to the west of Tupo Bay, beyond the limits of the effusives. 

Petrology. — Hand-specimens of most of the effusive and dyke rocks of this series are 
distinguishable from Wairakau and Kerikeri rocks by their decidedly altered character. 
The large phenocrysts, whether of feldspars or of ferro-magnesian minerals, are softened, 
and e\adentlv contain many decomposition-products. The groundmass has a dull, earthy 
appearance, very different from the fresh matrix of the more recent rocks. The very fine- 
grained compact flows associated with the tuffs and breccias a little to the east of the Sugar- 
loaf are, however, indistinguishable megascopically from Kerikeri flow rocks. 

Microscopically the characteristic type is a pyroxene-andesite in which hypersthene is 
the most abundant ferro-magnesian mineral, and the augite is occasionally replaced by horn- 
blende. The porphyritic feldspars, as a rule, show low extinction-angles. The groundmass 
is now considerably altered, but was probably originally finely granular (Plate XV, No. 3). 

Variations from this type are frequent, and are found within a few feet of one another 
—augite-, hornblende-, and hypersthene-andesites, and combinations of these, ha\'ing been 
determined from neighbouring localities. 

In some sections, iron-ores (magnetite and ilmenite), usually not noticeable, are very 
strongly developed, especially as inclusions in the phenocrysts, which are so thickly studded 
with granules as to become almost opaque. 

Frequently a considerable quantity of a radiately fibrous zeolite occurs in the flow rocks. 
An analysis of this mineral is as follows 

56-2 
13-6 



Silica (SiO,).. 
Alumina (AlgOj) 
Ferric oxide (FcjOg) 
Lime (CaO) . . 
Magnesia (MgO) 
Potash (KjO) 
Soda (Na^O) 
Water 



0-5 
31 
3-2 
0-8 
7-1 
15-5 



1000 



The mineral is apparently stilbite, in which the lime has been partially replaced by magnesia. 

* Ses Chapter VI, p. 80. 



79 



The fine-grained., compact, flow rocks near the Sugarloaf do not differ much in their micro 
scopic characteristics from the granulitic dolerites of the Kerikeri flows, except that they show 
more signs of decomposition and a far more decided, flow structure, and that the flow-lines of the 
smaller crystals enclose large corroded crystals of labradorite and olivine, the latter very much 
serpentinised. 

A porphyritic structure is, as a rule, more marked in the dyke rocks than in the flows. 

The pyroclastics are usually recognisable as such in hand-specimens. Their colour is 
dull grey, and they are considerably decomposed, although, where sufficiently coarse-grained, 
the constituent fragments of which the rock is composed can be distinguished. Stringers of 
quartz and calcite are abundant in some places. 

Areas of mineralisation also occur, notably one on the coast about half-way between 
Karaui and the Sugarloaf. Further reference to this will be found in Chapter VI, page 93. 

I'nder the microscope the pyroclastics are usually too much altered for their constituent 
minerals to be recognisable. The least altered of the finest-grained rocks are made up of 
comminuted fragments of p}Toxene8 and intermediate feldspars, often cemented together by 
calcite. The coarser fragments appear to agree in structure and mineralogical composition 
with the effusive and dyke rocks (Plate XV, No. 4). 

Large rock-fragments seldom enter into the constitution of these rocks, nor are the frag- 
ments rounded. In both respects the pyroclastics thus differ markedly from the Wairakau 
breccias. 

The following analy.ses of typical .specimens of (1) the pyrocla.stics, and (2) the associated 
lava-flows from the coast-line inside Cone Rock, show a marked agreement when allowance 
is made for the greater subsequent alteration of the fragmental rock : — 

Silica (SiOj) . . 
Alumina (AI2O3) 
Ferric oxide (Fe^Oj) . . 
Ferrous oxide (FeO) 
Manganous oxide (MnO) 
Lime (CaO) . . 
Magnesia (MgO) 
Potash (K,0) 
Soda (Na^O) . . 
Titanium-dioxide (TiOj) 
Carbonic anhydride (COj) 
Water and organic matter 

10000 10000 

Correlation and Age. — Although no constant petrological difference can be maintained 
between the rocks just described and those of the Wairakau Series, vet, in view of their nmch 
more extensive alteration and also of their greater degree of dislocation, it seems advisable 
to separate them as being older than the Wairakau rocks. 



No. 1. 


No. 2. 


50-71 


56- 10 


1718 


16-28 


016 


0-39 


5-33 


5-76 


0-35 


0-45 


645 


6-25 


4-71 


4-85 


210 


1-85 


2-12 


2-75 


0-84 


0-93 


4-35 


2-05 


5-70 


2-34 



80 



CHAPTER VI. 



ECONOMIC GEOLOGY. 





Page 




Page 


Introduction 


.. 80 


Coal 


. 95 


Cupriferous Sulphide Ores . . 


.. 80 


Kauri-gum 


. 96 


Ores of Mercury . . 


.. 87 


Mineral Oil 


. 96 


Occurrences of the Precious Metals 


in 


Building and Cement Stones 


. 97 


Sinter-deposits and Quartz Veins 


.. 92 


Mineral Waters 


. 97 


Iron-ore . . 


.. 93 


Sulphur . . 


. 98 


Oxides of Manganese 


.. 94 







Introduction. 

Although the Whangaroa Subdivision yields a considerable variety of valuable minerals, 
these seldom occur in sufficiently large deposits to be of importance. Geological occurrences 

of economic interest may be considered under the following heads : — 

(1.) Cupriferous sulphide ores. 

(2.) Ores of mercury. 

(3.) Occurrences of the precious metals in sinter-deposits and quartz veins. 

(4.) Iron-ore. 

(5.) Oxides of manganese. 

. (6.) Coal. 

(7.) Kauri-gum. 

(8.) Mineral oil. 

(9.) Building and cement stones. 

(10.) Mineral waters. 

(11.) Sulphur. 

Cupriferous Sulphide Ores. 

The cupriferous sulphide ores occur at altitudes varying from 400 ft. to 800 ft. on the 
slopes of Maungaemiemi Hill, overlooking the valleys of the Kaeo and Pupuke rivers. 

The ores are found in small, irregular, and much broken and faulted lensoid veins in soft 
shaly claystones and somewhat harder greyish sandstones belonging to the Kaeo Series. These 
rocks were originally capped by Kerikeri dolerites, which, with the exception of an outlier 
forming the top of Maungaemiemi, have now been removed by denudation. Apparently the 
ores always occur in close proximity to diabases and gabbros — of class (b) in the last division 
of Chapter V — and along zones of local faulting, where intense fracturing, pronounced slicken- 
siding, and the production of much soft clay gouge indicate earth-movements. The striated 
surface of fragments of the sulphide itself shows that faulting has been continued since the 
formation of the veins. Copper-ores seem to occur only, but by no means universally, in the 
above-mentioned zones of faulting, which are locally spoken of as " the formation," and which 
therefore serve to indicate " likely country." 

Mineralogically the ore consists mainly of marcasite and pyrite, with a considerable amount 
of chalcopyrite and with traces of covellite, malachite, bornite, native copper, and probably 
chalcocite. The marcasite and pyrite are generally finely crystalline, but occasionally the 
latter is seen in large regular cubic crystals. The chalcopyrite is also usually of fine grain, 
and intimately mixed with the two iron-sulphides, but in places it occurs in large, coarsely 
crystalline patches. The higher sulphides — bornite, chalcocite, and covellite — are rare, and 
appear generally only in very small patches, or as crusts on the more widespread poorer mineral. 



81 

Malachite also is infrequent, but is to be noted as occasional stains and as still rarer coatings 
on sulphide ore. Native copper is reported as occurring in a selvage at one point only — namely, 
near the No. 2 drive on the Hare-Ratjen propeity. 

The gangue-minerals associated with the ore consist mainly of calcite and quartz. Chlorite 
and serpentine are not infrequent in the slickensided material on the foot and hanging walls. 
The calcite is generally coarsely crystalline, but the quartz is usually very fine-grained and 
even flinty or jasperoid. More or less mineralised puggy country rock occurs with the metallic 
constituents of the veins. 

Small incrustations occur in some of the mine-workings. An analysis of such material 
obtained from a short drive in Frenchman Creek may he of interest. 

Silica (SiO,) .. .. .. .. .. .. 2(»-45 



Alumina (AljO,-,) 

Ferric oxide (FejO,) 

Lime (CaO) 

Magnesia (MgO) 

Iron-disulphidc (FeSj) 

Water, organic matter, and undetermined 



4-65 
0-25 
8-05 
1-50 
55-22 
9-88 



The deposit contains no mineral of economic value. 

A greenish incrustation on the face of a ledge over which a small waterfall descends just 
above the outcrop of the lode in Hare Creek was found to contain 0-20 p >r cent, of (topper. 

At the surface, excepting where exposed in the creek-beds, the outcrop of the sulphide ores 
shows a gossan of hydrous ferric oxide (limonite) containing only traces of copper. In places 
large masses of this gossan are strewn over the surface in the neighbourhood of the outcrop. 
The stream-channels near the lodes contain many fragments of gossan and some boulders ol 
the sulphide material itself. 

Though the sulphide bodies follow in general the structure of the enclosing sedimentaries, 
they are undoubted fissure-veins,* and the contained ores were introduced subsequently to the 
dislocation of the strata. The sulphides were probably deposited by copper-bearing hydro- 
thermal .solutions which accompanied or followed the intrusion of the gabbros and diabases 
above mentioned. The small amounts of gold aiul silver which the ores contain, belong to 
the same period of deposition. 

The formation of the gossan of iron-oxides, which marks the outcrop of the deposits on 
the hillsides, was probably contemporaneous with that of the small masses of enriched sulphides 
and of much of the secondary chalcopyrite. It is noteworthy that the gossan consists almost 
entirely of hydrous ferric oxide, and contains only traces of copper. Thus it may reasonably 
be presumed that the copper originally contained in the sulphides, of which the gossan is the 
oxidized equivalent, has gone to enrich the original sulphide at lower levels. The oxidation 
of the small amounts of chalcopyrite with the iron-sulphides would give, among other com- 
pounds, cuprous sulphate (CuSO^), and from this, lower down, would be precipitated, either 
by pyrite, marcasite, or chalcopyrite, the necessary copper material to produce either secondary 
chalcopyrite or higher copper-sulphides, as the case may be.| 

Indications of copper in the Pupuke Copper-field are widespread, but in most cases these 
indications consist only of boulders of go.ssan or sulphide material, and deposits in situ are 
verj- rare. A number of claims have been staked, the principal ones being those held by the 
Hare-Ratjen Company, the Whangaroa Amalgamated Company, and the Ferguson's Mining 
and Smelting Company. 

* As defined by Bec-k and Weed, ' The Nature of ()re-de))<).sits," 190.5, p. 1 12. 

t For a discus.sion of this process, see " The Secondary Enrichment of ('oinx-r-Irori Sulphides,'' by Thomas 
T. Read. Trans. Am. Inst, of Mining Knjlincers, vol. xx.xvii, p. 297. 
6 — Whangaroa. 



8-2 

Traces of copper in the shape ol tiny stringers of cupriferous sulphide occur also in Oika 
and Packhorse creeks and elsewhere in the Pupuke Copper-field. 

The workings of the Hare-Ratjen Company are situated in the headwaters of Awaiti 
and Maropiu creeks, which flow to the Pupuke. The workings entered at the present No. 1 
drive show no definite ore-body, though thin lenses are found in places in y)Uggy and much- 
shattered shal)' claystoue, and it is said that a distinct vein of very rich material, which later 
excavation has failed to reveal, was encountered in this locality, in the original No. 1 driN-e, 
which was obliterated by a slip. I.,arge masses of gossan lie on the sloping surface above the 
drive — sojue of a purplish-brown colour, others bright red. A sample of the gossan was found 
to contain 5()'4 per cent, of metallic iron and 0-34 per cent, of copper, but neither gold nor 
silver. In other samples no gold, silver, or copper could be detected. Just below and slightly 
to the southward of No. 1 drive is the drive known as No. 1a. No appreciable amount of 
sulpliide material is visible in this locality, though in places small lenses of ore are seen. 

The following analyses show the mineral-content of small occurrences of mineralised rock 
from various places in these workings : — 



)wt 


gr. 


Dwt. gr. 







2 


1 4 


Nil. 





1 


15 


0-16 





2 


() 10 


0-66 





1 


1 3 


0-()7 





1 


1 4 


Nil. 



Locality. JGold per Ton. Silver per Ton. Ojpper yter Cent . 



No. 1 drive, at entrance of second branch drive 

No. 1 drive, at about 50 links in from entrance 

No. 1 drive, second branch drive 

No. 1a drive, about 50 links from end 

No. 1a drive, about 30 hnks from mouth 

In the sinuous workings of No. 2 drive, ore appears at several places in definite veins, 
which, however, are nowhere very continuous. The tunnel as originally tlriven ran straight in 
from the mouth, but the inner part has now collapsed, and at 63 ft. from the entrance more 
recent workings, which are still open, deviate from the earlier excavation. C4ood ore is said 
to have been obtained from the innermost part of the original drive, which, however, caved in 
shortly after its construction, preventing an adequate examination of the deposit. Along the 
deviation drive, at about 100 ft. from its junction with the original drive, 5 ft. of sulphide 
ore is said to have been cut in a winze sunk in the drive-floor, but the ore is traceable only 
for some 6 ft. along the course of the excavation. Along the drive, from 16 ft. to 40 ft. 
beyond the previous point, a vein of sulphide ore is prominent, and then ceases abruptly 
(locality A in subjoined analyses.) The vein averages at least 3 ft. in thickness, strikes 
nearly north and south, and dips to the eastward at about 50°, is of fair quality, and is 
overlain and underlain by shaly claystones, which, in this neigbbourhood, appear to strike 
N.W. and S.E. and to dip to the north-east at varying angles. At some 23 ft. beyond the 
seam just described the drive turns almost at right-angles, and after traversing 28 ft. of barren 
country it cuts a vein of ore about 2 ft. wide (locality B). This vein is traceable for some 
13^ ft. in a general direction of north 80° east, when it dies out suddenly in small lenses in the 
fractured zone of country. 

Analvses of ore from No. 2 drive gave the following results : — 



Locality and Nature of Specimen. 


Gold per Ton. 


Silver per Ton. Copper per Cent. 


A. General sample . . 

B. General sample . . 


Dwt. ar. 
() 2 

2 


1 
Dwi. sr. 

7 13 4-17 
6 7 1-02 



PLATE XVI. 




Enthance to Hake and Uatjen's No. '2 Duive, 1'ui'uke Coi>i>ei:-field. 




Area No. 5. Ohabawai Hot Springs. 



Bulletin No. 8.] 



[Face p. 83. 



83 

Outside the entrance of No. 2 drive itself lie about 46 tons of ore, taken from various 
parts of the drive. The ore, which is much disintegrated, consists mainly of fine-grained 
marcasite, with minor patches of chalcopyrito and with occasional malachite stains. A 
careful sampling of the heap showed, on analysis, copper to the extent of 3-58 per cent. Much 
of the value in copper has been leached out through exposure. A general sample of iron- 
sulphide (which, from the action of nitric acid, appears to be mainly marcasite) from the ore- 
heap, picked free from chalcopyrite, yielded 15 gr. of gold and 5 dwt. 16 gr. of silver per ton, 
and no copper ; while a similarly selected sample of chalcopyrite contained 8 gr. of gold and 
9 dwt. 13 gr. of silver per ton, and 21-42 per cent, of copper. It thus appears that the values 
in gold and silver are fairly evenly distributed between the iron-sulphide and the chalcoj)yrite. 

Just above No. 2 drive are a number of excavations, mainly, the writers understand, 
made by the Ferguson ("ompany. The uppermo.st workings were apparently conducted on 
a prominent vein of sulphide which strikes diagonally across the creek-bed for about 24 ft. 
The hanging-wall consists of pyritous, shattered. Ijluish. shaly claystone. The foot-wall is 
not visible, but the maximum width of the vein is at lea.st 3 ft. 9 in. The ore is not rich, con- 
sisting chieHy of iron-sulphides with a small admixture of chalcopyrite. A representative 
sample taken from the 24 ft. of vein exposed was found to contain 7 gr. of gold and 9 dwt. 19 gr. 
of silver per ton, and 5-35 per cent, of copper. Where the vein disappears beneath the bank 
of debris on the upstream side, the sulphide-ore is disintegrated and mixed with whitish and 
rusty pug. The vein apparently follows the bedding of the hanging-wall shales, striking 
north and south, and dipping easterly at about 35°. On the downstream side of the ore-body, 
for some 35 ft. are the remains of an old adit, driven under and parallel to the creek-bed, and 
apparently on the sulphide vein. Several tons of high-grade sulphide lie on the surface above 
the drive. About 16 ft. below the mouth of the drive, along the stream-bed, another drive 
enters the right bank, from which sulphide ore in the form of '• Hoaters " is said to have been 
obtained, but no definite lode was encountered. 

Below the mouth of this drive, on the left bank of the stream, lie about 20 tons of good 
ore, consisting of marcasite, pyrite. chalcopyrite. and a little covellite. malachite, and perhaps 
chalcocite and bornite.* The folowing is an analysis of a picked uniform sample of this 
ore :— Per Cent. 

Copper .. .. .. 2013 

Iron . . . . . . 30-60 

Sulphur 40-77 

This would correspond o a formula <'n.,Ke,jS, ^,t which probably represents approximately 
the chemical composition of the best of the ore in this part of the Pupuke Copper-field. 

It seems very probable that the several occurrences of sulphide ore seen in No. 2 drive 
and in the creek-bed above the drive belong to the same lens of ore. broken by faulting ; 
but it is also possible that there may be more than one lens. 

All the old workings in Hare Creek — a tributarv of the Awaiti — have caved in, but two 
small ore-heaps, containing aljout 45 tons, testifv that some ore at least was taken from the 
several excavations. The ore in these heaps now contains only 0-99 per cent, copper. I'n- 
doubtedly much of the copper has been removed by leaching since exposure to the air. 

A sulphide vein appears in the shales of Hare Creek just below the workings. The vein 
lies almost horizontally, but has a slight general inclination to the west. On the west bank 
of the stream it is traceable in a general northerly direction for 12 ft. 3 in. On the down- 
stream side the seam appears to die out, while on the upstream side a sudden dip in the vein 



♦ It is very difficult in jtUces to a.sccrt»in the exact mineralogical character of the ore. owing to the 
small amount of each mineral sjxjcies present. 

t Report by Dr. J. S. Maclaurin, Dominion Analyst. 

6* — Whangaroa. 



5-61 


4-63 


42- 16 


11 -6^ 


4812 


47-60 


Nil 


Nil. 


16-29 


13-45 


79-50 


80-42 



84 

carries it beneath the surface. It is reported that beyond this abrupt change in inclination 
approximate horizoutality was resumed, and that the ore continued for at least 19 ft. more. 
Owing to the large quantity of debris in the creek-bed this statement could not be definitely 
confirmed. Where exposed along the west bank of the stream the vein varies in thickness 
from 1 7 in. to 33 in. At right-angles to the exposure, along the west bank of the stream, 
the vein increases in thickness to at least 42 in., and may be followed for 15 ft. to the point 
where it disappears beneath the bank of debris. It may continue beneath this eastern bank 
for some distance, and, since the floor or foot- wall is not seen, its thickness is probablv greater 
than the dimensions just given. The hanging-wall is a soft, bluish-grev shale. The quality 
of the ore is, in general, poor. It consists mainly of the iron-sulphides, with only occasional 
splashes of chalcopyrite. The results of analyses of two samples — (1) from the outcrop on the 
west bank of Hare Creek, and (2) from the continuation of the vein to the eastward— are given 
below : — 

No. 1. No. 2. 

Silica (SiOa) .. .. .. .. .. 1-53 2-50 

Copper* 

Iron* 

Sxilphur* 

Lime (CaO) 

* Equivalent to — 

Chalcopyrite (CuFeSj) 
P>Tite (FeSa) 

We are indebted to Mr. Charles Ratjen for some particulars with regard to the value 
of the ore from No. 2 drive. The analyses represent " all grades of ore that came to hand 
while work was being done." Mr. Ratjen, in his communication, remarks : — 

" One shipment of 12 tons of ore sent over to 8\dney to the English and Australasian 
Smelting Company gave the following returns : Lot No. 1, 6 tons, 8-225 per cent, copper; 
lot No. 2, 4 tons, 3-25 per cent, copper ; lot No. 3, 2 tons, 4-8 per cent, copper. I find that 
the average gold and silver contents of forty assays are — Gold, 8 gr. per ton (2,240 lb.) : silver, 
J oz. per ton (2,240 lb.). Although a gossan outcrop has gone as high as 6 dwt. 3 gr. per ton 
fine gold, and ore taken from No. 2 drive ran as high as 4 oz. silver per ton." 

On the Whangaroa Amalgamated Company's claim, extensive prospecting has been 
carried out in the neighbourhood of Bell's original discovery in Frenchman Creek (see " History 
of Mining," Chapter I, page 18). The boulders of sulphide — rich in chalcopyrite — of the 
original discovery are still visible at the so-called " outcrop " on Frenchman Creek. A general 
sample from these boulders yielded 1 dwt. 6 gr. of gold and 2 oz. 4 dwt. 2 gr. of silver per 
ton and 9-18 per cent, of copper. No. 4 drive, on the left bank of Frenchman Creek, was 
put in because of the large number of boulders of gossan* appearing at this point. In the 
300 ft. driven, two zones of shattered country were cut, and in each some very small lenses 
of sulphide, mostly pyrite and very low in chalcopyrite, were seen, but no definite vein 
was encomitered. In close proximity to the zones of shattered country or " formation " 
occurs the decomposed rock mentioned in Chapter V, page 77, and] locally knowTi as 
" serpentine." 

It is stated that the No. 3 drive on Moorcroft Creek was driven after a prospecting-drive 
somewhat higher up the creek had cut a zone of shattered copper-bearing country. Twenty- 
six feet in from the mouth of No. 3 drive the " lode-formation " — a zone of much-fractured 



* Samples from the gossan occurring near the lower end of Frenchman Creek yielded 0-21 per cent, of 
copper, while the gossan occurring near the head of the creek was found to contain no copper. 



85 



shaly country — appears, and persists thence to the end of the drive, 
of this " lode-formation " from No. 3 drive : — 



The following are analyses 



Silica (SiOj) . . 


. 42-30 


48-81 


Alumina (AljOg) 


. 21-35 


22-28 


Ferric oxide (FeaOj) . . 


0-20 


7-60 


Lime (CaO) .. 


2-20 


9-03 


Magnesia (MgO) 


1-80 


200 


Potash (KjO) 


0-96 


1-06 


Soda (Na^O) . . 


3-19 


308 


Titanium-dio.xide (TiOa) 


0-40 


0-95 


Iron-disulphide (FeS^) . . 


14-43 


Nil. 


Carbonic anhydride (CO 2) 


Nil 


0-37 


Water and organic matter 


13-17 


4-82 



10000 10000 

The high percentage of water and organic matter is doubtless due to the shattered and perme- 
able character of the rocks. It is noteworthy that the analyses show that the rock contains 
not even a trace of copper. 

At the end of the drive, which is 66 ft. long, a shaft was sunk some 70 ft. .\t this depth 
a zone of sulphidc-beariiig country 24 ft. wide and with well-defined walls is said to have been 
discovered. The vein, which was dipping in a north-west direction at about 45°, was followed 
down for 17 ft., when, unfortunately, the shaft had to be abandoned owing to inability to 
cope with the water. The (|uality of the ore. as judged from the large lumps in the shanty 
outside the drive, is good. The ore consists mainly of chalcopyrite, coated in places with 
bornite, with coarsely crystalline pyrite, and nmch calcite. It is evidently of secondary 
The following is a complete analysis of this enriched material : — 
Copper* . . . . . . 15-30 



origm. 



Sulphur* 

Iron* 

SiUca (SiOj) 

Alumina (AloOj) 

Calcium-carbonate (CaCOj) 

Magnesia (MgO) 

Water and undetermined 



26-68 

23-35 

14-05 

8-24 

11-75 

0-20 

0-43 



10000 

Gold Nil. 

Silver . . . . II dwt. H gr. per ton. 

* Equivalent to — 

Chalcopyrite .. ... .. .. 44-18 per cent. 

Pvrite .. .. .. 2115 

Recently a new shaft was .started some distance further west, with the object of cutting 
the vein of rich material above mentioned, and has reached a depth of 40 ft., but at present 
work is at a standstill. Its dimensions are 13 ft. by 4 ft., making provision for two winding- 
compartments and a ladder-way. 

As yet the Ferguson Company has found little to encourage further mining endeavour 
on the eastern side of Maungaemiemi. Near the head of Morrison Creek a drive has been put 
in some 390 ft. to intersect the so-called Knight's lode, a narrow, pyritised, shattered zone, 
the discovery of which was due to the finding of gossan. At a point 365 ft. along the drive 



86 



a zone of serpentinised shale supposed to represent the lode was cut, and a winze is being 
sunk thereon. In a few places small segregations of rich chalcopjTite-ore were encountered, 
but no continuous vein or even a definite lens. The shale, which commonly contains 
crystals of pyrite, is cut by diabase near the end of the drive. 

In the shaft on Gentle Creek, a tributary of the Kaeo River, several lenses of sulphide ore 
(pyrite and chalcopyrite) up to I ft. in thickness, but of no continuity, are said to have been 
cut. 

The following is a statement of the metalliferous content of samples from different localities 
in the Ferguson claim : — 



Locality. 


Gold 


per 


Ton. 


Silver per Ton. 


Copper per Cent. 






Gr. 




Dwt. gr. 




Oika Creek, just below mouth of Morrison Creek 




1 




1 4 


Nil. 


Excavation above drive on Knight's lode, in 




Nil 




Nil 


012 


Morrison Creek 












Old drive north of that in Morrison Creek 




Nil 




1 6 


Nil. 


Drive on Knight's lode, in Morrison Creek 




Nil 




1 6 


0-25 



Some prospecting was carried on by the Northern Minerals Company on the left 
bank of Te Patoa Creek, which joins the Pupuke River some distance to the west of the copper- 
field. An inclined shaft was put down for some depth, and o.her smaller excavations made. 
Ore is said to have been obtained, but apparently the prospects did not warrant a continuance 
of the work. The shaft is now filled with water, but a sample from so-called ore stacked at 
the mouth of the drive, and apparently fresh, yielded no metals of value. The following is the 
result of an analysis of this sample • — 



Silica (SiO^) 

Alumina (AlgOg) 

Ferric oxide (FejOg) 

Lime (CaO) 

Magnesia (MgO) 

Iron-disulphide (FeSj) 

Water, organic matter, and undetermined 



56-68 
1504 
1-77 
9-60 
110 
8-38 
7-43 



10000 

From the foregoing paragraphs it will be gathered that, though comparatively little has 
yet been definitely ascertained regarding the downward extension of the Whangaroa copper- 
deposits, what is known suggests that the deposits are inextensive. 

It is natural to expect lensoid and not very continuous veins in stratified argillaceous 
rocks, but at Whangaroa there is the additional uncertainty presented b}' repeated faulting 
since the formation of the ore-bodies. The ore itself, though generally of low grade, is ap- 
parently one suitable for metallurgical treatment by pyritic smelting, though it seems probable 
that some siliceous flux, and no doubt a small amount of coke, would have to be added to 
the charge. 

Though the Whangaroa Amalgamated Company's claim exhibits in general the highest- 
grade ore, the Hare-Ratjen property shows the largest bodies of ore yet discovered. Further 
exploration of the veins outcropping in Awaiti Creek near the No. 2 drive, and in Hare Creek, 
is distinctly warranted by the promising surface-indications. 

To sum up, at Whangaroa we have an ore, which would apparently be easy to smelt, 
occurriue in small and uncertain veins in much-faulted country, and consequently expensive 



87 

to mine. If ore of the high quality discovered in the old shaft on the Whangaroa Amalgamated 
Claim be proved to exist in sufficient quantity, a distinct impetus will be given to mining on 
the field. It is probable that then the two companies — the Hare-Ratjeu and the Whangaroa 
Amalgamated — could operate with success a small pyrite-smelter, which might conveniently 
be located on the low-lying country towards the Pupuke River. 

Ores of Mercury. 

Ores of mercury have been discovered at several points in the Whangaroa Subdivision. 
Some years ago Messrs. Hare Brothers and Broun, of Kaeo, found a specimen of high-grade 
cinnabar (mercuric sulphide) in one of the tributaries of Waikoura Creek. The lump weighed 
over 4 lb., and contained 65-66 per cent, of sulphide of mercury (equivalent to 56-60 per cent. 
of mercury). Diligent search by the discoverers, together with later examinations by officers 
of the Geological Survey, failed to reveal any parent lode, but it is probable that the deposit 
from which it was derived lies concealed beneath the surface debris in the neighbourhood of 
the Huia Hill. 

Some time ago many small fragments of cinnabar of good quality were discovered on the 
lava tableland to the east of the Huia, but no definite lode was ever obtained. It is not un- 
likely that the lump found in Waikoura Creek and the fragments picked up on the tableland 
above are from the same deposit, which is probably a result of the fumarolic activity suc- 
ceeding the extrusion of the Kerikeri volcanics. 

Much the most important occurrence of mercury -ore is, however, at the Oliaeawai Hot 
Springs, in the Ngawha Lake basin, and here an effort has been made to mine the ore and 
retort the mercury therefrom. The deposits definitely occur in five localities -at Waitetera 
Pond, and in areas Nos. 1, 2, 3, and 5, all close together in the immediate neighbourhood of 
the hot springs (see detailed map). These will be described later in detail. The mercury- 
content of the ore lies mainly in cinnal)ar. but native mercury is also to be seen. The cinnabar 
and native mercury are associated with sulphur and marcasite, bituminous matter and hydro- 
carbons, a lesser amount of chalcedonic quartz, and a little stibnite, and occurs as irregular 
impregnations in the more or less sinterised (silicified) hi<:hly carbonaceous sands and clays 
of the Ngawha Lake basin. The mineral (probably metacinnabarite*) mentioned by Captain 
Huttonf a» occurring in connection with the deposits was not observed by the writers. 

The mercury-deposits of Ohaeawai bear in many ways a striking resemblance to those 
of Steamboat Springs, Nevada, and Sulphur Bank, California. Mr. G. F. Becker, in his de- 
scription! of these remarkable occurrences, considers that the mercuric sulphide came up in solu- 
tion as a double sulphide of mercury and an alkali, and he is of opinion that bituminous sub- 
stances have strongl}^ influenced precipitation at the surface. Since the waters of sonu' of the 
Ohaeawai hot springs are rich in alkaline salts, and also contain hydrogen-sulphide (as may 
be seen by a glance at the analyses, tliapter IH, pages .'i7-.'i9), it seems probable that the double 
sulphides of mercury and the alkalis exist in .solution at horizons of increased temperature 
and pressure beneath the surface, and become dissociated higher up, with the consequent 
deposition of sulphides of- mercury. There can be little doubt, moreover, that here, as 
believed bj- Becker§ in connection with the Nevada deposits. Vjituminous matter has very 
strongly influenced the precipitation of the mercuric sulphide, for almost everywhere 
where the mercurv-ores appear, bituminous matter is to be seen, and coatings of cinnabar 
are frequently found on the carbonised roots of kauri-trees in the lacustrine beds, and 



• Dana, " System of .Mineralogy," 1904, p. 63. 

"•f" On the Occurrence of Native Mercury near Pakaraka, Bay of Islands," Trans., vol. iii, 1870, p. 252. 

+ •• Mineral Resources of the United States," 1892, i>. 1.51, &c. 

J Loc. cil., p. 152. 



88 

have been reported as occurring on the kauri-gum,* occasionally to be seen in the clays 
and sandstones which the mercury-ores have impregnated. It is of interest also to note the 
occurrence of methane in the gas evolved in the neighbourhood of the mercury-deposits. f 
Presence of bituminous matter became particularly evident in the metallurgical process of 
distillation where the bituminous matter was driven off along with the mercury, and, con- 
densing with it, formed a film on the surface of the globules which prevented their coalescence, 
and consequently rendered the collection of the mercury a difficult matter. For this reason 
the abundant petroliferous content of the Ohaeawai mercury-ore detracts considerably from 
its economic value (see page 89). It is quite possible that other substances in solution 
in the hot waters may have also aided in precipitation, such as an excess of hydrogen- 
sulphide ; again, n mere dilution by cool surface-water may have had the same efiect. 

Though the rocks in which the Ohaeawai mercury-ores lie are entirely sedimentary, being, 
as pre\aously stated, lacustrine clays and sandstones of probable post-Miocene date, in close 
proximity to the deposits are igneous rocks belonging to the Kerikeri Series (see page 70). 
Since, however, these older volcanics caused (by damming) the formation of the water-basin 
in which the lake-beds were deposited, it is hardly possible to regard them as the immediate 
source of the mercury-bearing solutions, which it is very probable are connected with the 
hydrothermal after-actions of the most recent period of volcanic activity. Doubtless this 
activity first displayed itself by explosive geyser-action, as evidenced by the craters in which 
the ponds and hot springs are found, and by the much -shattered though silicified character 
of the lacustrine beds in and around the mercury-deposits. In the opinion of the writers 
the ores of mercury have impregnated rather than metasomatically replaced the strata in 
which they are found. 

As shown by the anah'ses, pages 37-39, none of the Ohaeawai hot springs are now deposit- 
ing mercury, excepting the springs, or perhaps more correctly the escaping vapours, in No. 3 
area. It is, however, quite possible that the ascending mercury-bearing solutions are robbed 
of their mercury-content some little distance below the surface, precipitation being there 
induced by decrease in pressure and temperature. 

In vol. ii of the " Transactions of the New Zealand Institute of Mining Engineers,"J Mr. 
Andre P. Griffiths gives a very complete description of the mercury-deposits and the plant 
erected for the treatment of the ores. His remarks concerning the plant, which is still standing 
and in fair condition, are so descriptive that they may be given in full :— 

" The plant consists essentially of cast-iron retorts and brick condensing-chambers, 
placed in series of two, heated by one fireplace, and of a series of condensing-chambers. Owing 
to the scarcity of water at the works, the condensing-chambers were made of thin brickwork, 
offering a large cooling and condensing area. The fumes of quicksilver, together with the other 
gases produced by the distillation of the ore, pass from one chamber to another, following an up- 
and-down course, and finally are let into large wrought-iron tanks containing water, close 
to the surface of which the fumes were brought before finally being allowed to discharge into 
the exhaust-chimney. 

" The retorts are .^"N shaped. 3 ft. wide, 18 in. high, and 9 ft. 6 in. long from the door 
to the goose-neck leading into the first condensing-chamber ; the thickness of the metal is 
l^in., and the capacity of each retort is 1^- tons per twenty-four hours. The retorts have 
an inclination towards the front of the furnace of 1^ ft. They are pro^^ded with an air-tight 
door, having a sliding baffle-plate 8 in. wide and 10 in. high, enabling the draught through 
the retorts to be nicely regulated. Through the opening, moreover, the rabbling of the spent 

* " The Ohaeawai Quicksilver-deposits," by Andre P. Griffiths, Trans., N.Z. Inst. Mining Engineers, 
vol. ii, 1898, p. 48. 

t Cf. Becker, loc. cit., p. 152. 

J " The Ohaeawai Quicksilver-de])osits," Trans. N.Z. Inst. Mining Engineers, vol. ii, 1898, p. 48, 



8& 

ore is done, and the progress of the distillation can be watched by the furnaceman. At the 
upper end the retorts are provided with an automatic hopper, having an air-tight lid, through 
which the charges are introduced without the escape of any fumes. Moreover, in order to 
reduce the danger of salivation to a niininiuni, the front of each retort is provided with a 
movable hood and a shoot leading into a water-tank into which the spent ore is rabbled, 
any dust formed being immediately drawn back into the retort by the draught. The latter 
is regulated by means of a small fire lighted at the foot of the exhaust-stack. 

" The first chambers are 6^ ft. long, 9 ft. high, and 5 ft. wide, having a surface of 252^ 
square feet : the second chambers are 4 ft. long, 7i| ft. high, and 4i ft. wide, having a surface of 
153 square feet. Each retort leads separately into two of these chambers, but there is only 
one wrought-iron tank to each four chambers. These tanks are 4 ft. wide, 4 ft. deep, and 
10 ft. long. The two sets of furnaces have a total coolin}.'-surface of over 2,100 square feet, 
and each chamber is provided with a wrought-irou door, giving access to the interior. 

" The (juicksilver, after condensing on the sides of the chambers, trickles down to the 
Hoor, and is led l)y gravitation into small wroujiht-iron tanks, placed on each side of the furnace. 
From these tanks, which have a cover with hinges and padlock, the condensed (|uicksilver 
is ladled out and put into the usual wrought-iron bottles with screwed stopper, holding 75 11). 
of mercury. 

" The grate-area is 17^ square feet, being 5 ft. long by 3^ ft. wide. Firewood (puriri) 
was used as fuel, the consumption being about 1 ton per ton of ore. Flach furnace is provided 
with a smoke-stack and damper. 

" The retorts were not worked to their full capacity, only about 2i tons of ore being treated 
in each furnace per twenty- four hours, in charges of 1 cwt. The total cost for the twenty-four 
hours was as follows : — 

Six men, at 7s. 6d. 

One boy . . 

One foreman, at 10s., half to mining account 

Firewood, 2 tons, at lOs. . . 

Lime, lights, &c. . . 



Or a total cost of 16s. per ton ; this, however, could have been reduced to about 12s. bv working 
the furnaces at their full capacity. 

" Repairs are not taken into account, as there were none during the period the furnaces 
were kept at work. 

" The presence of a large amount of native sulphur and greasy hydrocarbon greatly inter- 
fered with the proper working of the furnaces. The hrst in contact with the iron of the retorts 
corroded them ^ireatly ; this was remedied by lining the bottom with firebricks, and bv the 
use of lime mixed with the ore, but the presence of the hydrocarbons presented an almost 
insurmountable difficulty. The globules of quicksilver distilled became coated with oily 
matter, which prevented them from coalescing, and caused a certain amount of quicksilver to 
be carried into the exhaust ; moreover, the mercury as it came out of the condensing-chambers 
was in a very fine state of division, the result of the oily matter contained in the ore. This 
' flouring ' of the quicksilver, due to the presence of a thin film of oil over each globule, often 
caused it to float on the water used for washing down the chambers. 

" In order to prepare the quicksilver for the market, the finely divided globules were 
first of all thoroughly washed in lime-water and then dried in finely sifted wood ashes or 
lime, which took up any moisture. The quicksilver was then strained through a filter and then 
bottled. 



£ 


s. 


d. 


.. 2 


5 





.. 


5 





.. 


5 





.. 1 








.. 


5 





£4 









90 



" The treatment of the soot was very similar, with this difference : that it was first 
thoroughly mixed with lime and worked and reworked on a cement floor, in order to extract 
all the coarser globules of the quicksilver, and afterwards treated with lime in a small distilling- 
retort. 

" The value of the ore treated varied from ^ to 5 per cent., the average being about H per 
cent. The average extraction amoimted to about 70 per cent, of the total contents of the ore. 

■■ The temperature of the exhaust gases varied from 90^ to 98" Fahr." 

The writers understand that in actual practice lime was never mixed with the mercury-ore. 
As a filter, four thicknesses of heavy calico were employed. The plant suffered greatly from 
scarcity of water — a difficulty which would certainly have been obviated had a site some 
distance down the valley near Tuwhakino Pond been chosen. With the amount of water avail- 
able, the condensers were too few in number and too close to the exhaust-pipe. 

All round AVaitetera Pond, where, as mentioned in Chapter III, page 35, violent ebulli- 
tions of gas composed of carbon-dioxide, methane, nitrogen, and hydi'ogen-sulphide take place, 
traces of cinnabar are said to have been found, and some rich material located in a drive near- 
by. Mercury-ores were noted by the writers in one place only — namely, on the north side 
of the pool to the left of the small stream entering from the Little Waitetera Pond. Here 
were seen, in long, narrow, almost vertical cracks in soft carbonaceous clays, very fine selvages 
and small hard pellets of bright-carmine cinnabar, together with some very fine globules of 
metallic mercury. 

Owing to the small amount of mercury-ore Ansible at Waitetera, the deposit cannot be 
said to present any great possibility. 

Brownish sinters occur in small amount at the outlet of Waitetera Pond. Appended 
are — (1) A general analysis, (2) the results of iin examination of these sinters for metals : — 



1. 



2. 



SiUca .. 


. . 91-80 


Mercuric sulphide (HgS) 


Nil. 


Iron-oxides and alumina 


2-50 


Antimony-trisulphide (Sb jS 3 ) 


005 per cent. 


Lime 


040 


Manganous oxide . . 


003 


Magnesia . . 


0-20 


Gold 


Nil. 


Loss on ignition . . 


510 


Silver 


8 gr. per ton. 



10000 i 

The surface of area No. 2 is very irregular, mainly, apparently, on account of a rude 
dissection by the waters from the various tiny pools and springs flowing to the main stream. 
At various places occur deposits of a silicified sintery sand, no doubt belonging to the Ngawha 
Lake beds. Near the south-west corner of the area, excavation in the muddy carbonaceous 
sinter revealed cinnabar and native sulphur deposited together as thin coatings on small some- 
what carbonised kauri-trunks. 

The results of (1) a general analysis of the more silicified sintery deposits, (2) an examination 
of this sinter for metals, (3) an examination for metals of a general sample of the muddy 
carbonaceous material from the southern part of the area, are as follows : — 

1. 2. 3. 





Per Cent. 


SiUca 


. 96-57 


Iron-oxides and alumina 


. 1-82 


Lime 


. 0-17 


Magnesia 


. 0-20 


Loss on ignition . . 


. 0-94 



Per Cenl 


Per Cent. 


Mercuric sulphide (HgS) . . 0-11 


3-25 


Equivalent to metallic mercury . . 0-10 


2-80 


Antimony-trisulphide (SboSg) .. 0-10 


0-25 


Manganous oxide (MnO) . . 0-05 
Oold .. .. .. NU 

Silver . . . . 8 gr. per ton J 


Not deter- 
mined. 



100-00 



91 

Panning in the creek traversing area No. 2 gave some fine grains of marcasite and a few 
grains of cinnabar of about the size of a pin-head. 

From the standpoint of a defined mercury-deposit of any economic value this area is 
not promising. 

To the south of area No. 2 a little sinter with sulphur is visible on a Hat surface of car- 
bonaceous clays, the site of a bore-hole. Cinnabar is said to have been obtained from this 
point, but none could be found by the authors. 

Area No. 1 is probably an old explosion-crater, but the extensive artificial excavations have 
nearly destroyed its original outline. The lake-ljeds appear intact on the edge of the cavity, 
especially in the artificial trough through which the streamlet running past No. 2 shaft flows. 
Here the beds exhibit a decided tilt in a northerly direction. The original surface of the 
area, which covers about a third of an acre, has been lowered some 6 ft. by artificial excava- 
tion. It is said that most of the material thus taken out went to the retorts, though some 
was not sufficiently rich to warrant treatment. Almost all over the surface of the area traces 
of cinnabar in thin selvages are to be found, and it is said that some metallic mercury was 
taken out during mining operations. It is not known to what depth mercuric impregnations 
occur. By far the richest material was obtained in the neighbourhood of the No. 2 shaft. 
which was sunk some 30 ft. or 40 ft. in the centre of the excavation. The shaft, which was 
abandoned during mining operations owing to the very high temperature encountered, is 
now filled with cold water, and from its surface, as well as from the several pools in the vicinity 
of the streamlet draining the area, various gases are strongly evolved (see Chapter 111. 
page 39). 

The rich patch mentioned above occurs just to the east of the sliaft, and is said to have 
been about 1 ft. thick, and fairly solid, and to have covered an area of about 16 square yards, 
with a slight dip in a westerly direction. In this locality some fine ore, consisting of cinnabar 
occurring in crusts with marcasite, a little siliceous sinter and native sulphur, can be obtained 
by digging in the soft mud. The largest of the pieces off cinnabar, marcasite, and sulphur 
are 4 in. or 5 in. long by 2 in. or 3 in. wide. The order of deposition of the nifrcury, sulphur, 
and marcasite is not con.stant, i)ut it appears that most frecpiently either sul])hur or marcasite 
occupies the interior of the lumps of ore, the cinnabar being encrusted on the outside. Sulphur 
is coating the timV>ers of No. 2 shaft. In colunm I below is given the result of the examination 
for metals of a representative sample from all over the surface, from which the best of the ore 
was taken. In column 2 is given the metal-content of a sample of the carbonaceous day 
taken round the edge of No. 2 shaft. Column 3 gives the results from a typical sample of 
the fragments rich in cinnabar. 

I. 
(Jold .. .. .. Nil 

Silver . . . . . . ,, 

Mercury . . . . 0-90 per cent. 

Sulphide of antimony 010 ,, 

Manganous oxide . . . . 005 ,, 

Other metals . . Nil 

Area No. 1 contains more visible mercury-ore than any other of the mercury-bearing areas 
at the Ohaeawai Hot Springs. 

The so-called mercury springs (area No. 3) are not really " springs," since little or no water 
issues therefrom, though steam-jets render the ground hot in places. In the carbonaceous 
clays and sands at the bottom of the depression a little metallic mercury is obtainable, and 
selvages of ciimabar are said also to have been located. laying on the carbonaceous clays 
and sands are many large and irregular fragments of spongy, sulphurous, sintery, carbonaceous 



2. 


:!. 


Nil 


0-5 gr. per ton 


1 2 gr. per ton 


10-0 gr. „ 


0-25 per cent. 


12-35 per cent. 


0-30 


005 


010 


010 „ 



No. 2. 


No. 3. 


i gr. per ton 


Nil. 


6 gr. 


10 gr. per ton. 


0-15 per cent. 


Nil. 


015 


0-50 per cent. 


0-10 „ 


0-20 „ 



92 

clays. An exainination of three aamples of these sinters for metals gave the following re- 
sults : — 

No. 1. 
Gold . . . . . . 1 gr. per ton 

Silver .. .. . . 6 gr. 

Mercury . . . . . . Nil 

Antimony -trisulphide (SbjSa) .. 0-25 per cent. 
Manganous oxide (MnO) .. 0-40 ,, 

On the " Maori Reserve " (area No. 5) excavations for ores of mercury are limited to 
the right side of the stream, where alone, in fact, evidences of the metal appear. Formerly, 
before mining started, a stratum some 3 ft. or 4 ft. thick and a little more than 900 square 
vards in area, carrjang ores of mercury, lay on this side of the stream. Now much of this 
is gone, but a block about 3 ft. thick, and covering an area of 363 square yards, still remains. 
On the surface of this block several hundred tons of loose, broken-up ore is stacked. 

The ore, as usual, appears in much-sinterised carbonaceous clays and sandstones, which 
represent reassorted Ngawha Lake beds. Small cavities coated with sulphur and alum are 
common, and a few crystals of stibnite and crusts of realgar were seen. The sinterised clays 
and sandstones are in places brecciated, and thin coatings of cinnabar not uncommonly occur 
in the cavities between the hard, angular fragments. Thin selvages of the mineral were also 
observed in places in carbonaceous clays. The sinter is occasionally coloured bright red and 
brown by iron-oxides. 

The following are the results of the examination for metals of the ore in area No. 5. Nos. 1 
and 2 are general samples from the ore-heap ; No. 3 is a general sample from the ore still in situ ; 
and No. 4 is a sample from the ore in the neighbourhood of the spring marked 1 on the detailed 
map. 

Gold 

Silver 

Mercury 

Antimony - trisulphide 

(SbaSg) .. 
Manganous oxide 

When mining was being conducted in this locality little or no excavation was carried 
out beneath the surface, consequently it is not known whether or not the ores go down. 

The mercury-bearing hot springs at Ohaeawai are features of considerable scientific 
interest, and they are also of some commercial value. The two most promising areas from 
a mining point of view are certainly Nus. I and 5. Though the ore is low grade, mercury 
undoubtedly occurs in both places in some quantity. The actual amount can only be ascer- 
tained by careful boring -experiments. If a sufficient quantity of sinter carrying even 0-9 per 
cent, of metallic mercury exists, mining operations could be carried on with a reasonable hope 
of success. The high-temperature difficulty could be in great part overcome by mining in 
wide open pits. The writers would also suggest that the feasibility of dredging might be 
considered. 

Occurrences of the Precious Metals in Sinter-deposits and Quartz Veins. 

Of considerable interest are the occurrences of the precious metals in sinter -deposits. 
A minute quantity of gold was detected in the water of the hot spring marked 1 in Area 5 
at the hot springs (see Chapter III, page 38). It will be noted in the preceding section 
that small quantities of gold or silver, or both, have been found associated with mercury in 



No. 1. 


No. 2. 


No. 3. 


No. 4. 


Nil 


Nil 


Nil 


4 gr. per ton 


10 gr. per ton 


>> 


)) 


11 gr. „ 


0-25 per cent. 


0-15 per cent. 


0-05 per cent. 


0-05 per cent. 


0-30 „ 


0-25 „ 


0-50 „ 


015 „ 


0-15 


0-05 „ 


0-20 „ 


0-20 



PLATE XVII. 




Ahea No. 5. OnAKAWAi Hot Si-itixos. 
Shows stacked ore, and ore in i<ilu. 




Bulletin No. 8.] 



Reductiox-works, Ohaeawai Hot Sprinqs 



[Face p. 9S. 



93 

Areas 1, 2, 3, and 5. The sintery deposits at (1) the Upper Sulphur Pond, and (2) the 
small area between Area 5 and Tuwhakino Pond were examined for various metals, with 
the following results : — No. 1. No. 2. 

Gold, in grains, per ton . . . . Nil 1 

Silver, „ „ .. .. 10 10 

Antimony-trisulphide (Sb^Sj) .. Nil 010 per cent. 

Manganous o.\ide (MnO) .. .. 0-15 per cent. 010 

The sinter of Neilson's so-called soda spring (see page 37) contains 8 gr. of gold and 1 dwt. 
6 gr. of silver per ton, also 0-05 per cent, of manganous o.xide. The sinter of the Waikoura 
" soda " spring contains 1 gr. of gold per ton and 0-2 per cent, of manganous o.xide. 

The gold- and silver-content of the sulphide ores of tlir Pupuke Copper-field has been 
already mentioned. 

Quartz stringers an; found fairly frccjuently in the W'aipapa and Kaeo rocks tiiroughout 
the Whangaroa Subdivision. The (juartz is generally finely crj'stalline. Definite quartz veins 
of any size are limited to the Kaeo rocks, with the exception of a 5 ft. vein of dark, barren 
(juartz occurring in Waipapa rocks, in Waikape Creek, two miles above its junction with the 
Waipapa River. A small vein, 18 in. thick, is situated at the head of Whitehead Creek, and 
has been driven on for 12 ft. Samples of the vein-stone yielded only 1 dwt. 6 gr. of silver 
per ton ; the couJitry rock from the foot-wall gave 2 gr. of gold and 1 dwt. 4 gr. of silver per 
ton, and that from the hanging-wall gave 1 gr. of gold and 1 d\s-t. 5 gr. of silver per ton. Definite 
but small and generallv l)arren veins occur in the Waikoura, Huia, and Waikare creeks, entering 
the Kaeo River below Kaeo Township. The vein-stone of some of these is fairly crystalline, 
and even shows medial drusy cavities. A (juartz vein about 8 in. wide in the Waikoura fteek, 
some little distance below the dam, on being assayed yielded 1 gr. of gold and 10 gr. of silver 
per ton. Ju.st under the lower dam on the Huia Creek,* a vein 4 J in. wide, which is trace- 
able for some yards in a north-east and south-west direction, and dips steeply to south-east, 
assays at 3 gr. of gold and I dwt. 18 gr. of .silver per ton. 

Stringers bearing pyrite, sphalerite, and galena were discovered in gruuwackes of the 
Waipapa Series in close proximity to andesitic dykes on the coast west of Tupo Bay. Samples 
from these seams contain 15 gr. of gold and 3 oz. 4 dwt. H gr. of silver to the ton, as well as 
4-96 per cent, of lead, 1-24 per cent, of zinc, and 015 per cent, of copper. Samples of other 
stringers from near the .same place yielded 15 gr. of gold and 3 dwt. 3 gr. of silver per ton. 
Another sample yielded 2 dwt. 11 gr. of silver per ton, while segregations of pyrite from the 
same locality yielded 6 dwt. 7 gr. of gold and I oz. 6 dwt. II gr. of silver per ton, also 009 
per cent, of copper. Small stringers of barren black (|uartz containing 0-42 per cent, of 
manganous oxide (MnO) occur in the same neighbourhood, wliich might perluips l)c fuither pro- 
spected with advantage. 

The effusive and pyrodastic rocks at the eastern point of a small huv about lialf a mile 
east of the Sugarloaf are decomposed, and impregnated with (piaitz and ])vrite. Samples 
from this locality gave 15 gr. of gold and 13 dwt. 5 gr. of silver per ton. Quartz veinlets 
in the same rock a few chains west of Karaui Point contain I dwt. 6 gr. of silver per ton. 

The igneous rock, post- Waipapa and probably post- Kaeo in age. at the south-east end 
of Cone Rock is slightly mineralised, and contains small stringers of (juartz, which yield 
silver at the rate of 1 dwt. 6 gr. per ton. 

Iron-ore. 

Iron-ore, always in the form of limonite, is found in many places in the Whangaroa Sub- 
division. Probably the largest amount occurs near the Potaetupuhi Hush, on the road from 



* Thi.s dam i.-i not marked on the map. 



No. 2. 


No. 3. 


No. 4. 


No. 5 


22-01 


16-51 


15-40 


. . 


38-93 


72-69 


60-69 


74-04 


27-25 


50-88 


42-48 


51-83 



04 

Okaihau to Kerikeri. The deposit is not continuous, but occurs in five small isolated patches, 
the total area of which is about 10 acres, while the thickness of the ore never exceeds 4 ft. — 
a fact proved by careful prospecting with hand junipers and drills. Beneath the limonite 
lies a soft, unctuous, yellow clay, with small strinjiors of limonite I'm. to i in. thick. Though 
the quality of the ore is excellent, as shown by the analyses, the <}uantity — of less than 
100,000 tons- — is quite inadequate for any commercial enterprise. The ore forms verv 
excellent metal for the roads in the neighbourhood. 

Near the Settlement of Pungaere, on the road from Pungaere to Kerikeri, and again on 
the ridge between the Pungaere and Kohatu Whakangaongao creeks, small deposits of .similar 
limonite occur. These never exceed 3 ft. in thickness, and cover but a small area. 

On the road from Pungaere to Mr. Copelands house small lumps of limonite are fourul 
ill places, but no defbiite deposit was located. 

The limonite gossan of the copper-deposits has already been described (sec page 81). 

Inferior deposits of red ochre — the " kokowai " of the Maoris — are found on various parts 
of the old lava tableland, notably near Trigonometrical Station H of the Omapere Survev 
District. 

The following are analyses of iron-ores from the Okaihau and Pungaere deposits : — 

No. 1. 
Moisture and organic matter 20-73 
Ferric oxide . . .. 73-14 

Equivalent to metallic iron 51-20 

No. 1 is an average sample from the outcrop to the north of the Kerikeri-Okaihau Road, 
and about half a mile south-west of Trigonometrical Station .13. 

No. 2 is a low-grade ore from the outcrop about three-quarters of a mile north-east of J3. 

No. 3 is an average sample from the outcrop about 25 chains south of .73. 

No. 4 is an average sample from the outcrop occurring about a quarter of a mile north 
of the Pungaere-Kerikeri Road, one mile from Pungaere. 

No. 5 is a sample of the scattered ore which occurs along the road between Pungaere 
and Mr. Copeland's house. 

The iron-oxides, which constitute all the deposits, are in the main derived from the Kerikeri 
volcanics. Probablv in the majority of cases the ferruginous material occurring in the volcanics 
was dissolved out liy carbon-dioxide-bearing surface-waters as ferrous carbonate. This 
carbonate was carried in solution to the swampy depressions on the volcanic tableland, where, 
on continuous exposure to the air, the ferrous carbonate was oxidized, and sank to the bottom 
as hydrous ferric oxide. In time a considerable deposit resulted. Thus, in fact, beds of iron- 
ore are forming to-day in swamps on the later basic lavas and all over the tableland of Kerikeri 
lava along the eastern margin of the subdivision. 

The interesting deposition of iron-ore being effected by a small spring near Mr. .J. D. Kemp's 
house, as mentioned in Chapter III, suggests that mineral springs, probably connected with 
the later manifestations of volcanic activity, may also have played a considerable part in the 
leaching-out of iron from the igneous rocks. 

Oxides of Manganese. 
Thin and irregular seams of limonite carrving more or less oxide of manganese are found 
in numerous places in the Waipapa argillites and quartzites on the coast east of Whangaroa 
Heads. One of these, seen on the isthmus at the base of Omiru Peninsula, contains 15-74 per 
cent, of manganese-dioxide (MnO.,) and 2-88 per cent, of manganous oxide (MnO). Other 
seams, however, from the same neighbourhood yielded only 0-2 per cent, of manganous oxide. 
On the Waipapa River, just above the Waikape junction, a seam 1 ft, to 3 ft. thick of man- 



95 

gaiiese-ore, containing 2845 per cent, of manganese-dioxide and 1-90 per cent, of niaiifjanous 
o.xide, was traced for 15 yards. The seam strikes about north-north-east and soutli-south- 
west, and dips to the west at a low an<ih\ The mineral of the Oniirn and VVai])apa deposits 
is chiefly psilonielanc. 

On the eastern side (jf Kairauwarn Bay small and irrejiular seams of manganese-oxide 
(psilomelane) occur in the contemporaneous igneous rocks. This yields .'51 -01 per cent, of 
manganese-dioxide (MnO^) ami 2-60 per cent, of manganons o.xide (MnO). 

!.arj.'(' hini])s of calcite containing a little manganese-oxide arc found in the i)ed of the 
.Mangakino ahout a mile and three-cjuaiters above its junction with Nip Creek. Masses of 
impure mangane.se-oxitlc are not uncommon in the neighbourhood of Puketi. 

Hcfciciices to a few other (;\en less important occurrences of manganese-oxide will i)c 
found in diaptci- TV, page 45. Mention of traces in sinters has already i)e(Mi made. • 

Coal. 

Lignites of ])Oor (juaiity are found in several places within the suli(li\ ision. They cannot 
be considered to be of any commercial value. Further particulars will be found near tin; end 
of Chapter V, page 71. 

Large lumps of a good pitch-coal occur in the small stream which enters the l^jjokorau 
between the mouths of Coal and Maria creeks. This stream and the neighbouring gullies 
were carefully examined, and excavations made in favourable localities, without discovering 
any definite seam. The best prospects were obtained at the head of the small tributary of the 
Upokorau above mentioned. Here was found a stratum 1 ft. thick, made up of broken piece.s 
of coal mixed with a blue clay. A much decomposed, apparently andesitic, lava-tlow seems 
to overlie the rocks in which this stratum occurs. McKay, after several attempts to locate 
the parent seam of coal, concluded that " the coal is not of Cretaceo-Tertiary age. l)ut occurs 
at the base of the great series of volcanic breccias that cover a large part of the northern district 
of Auckland."* It seems (piite possible, howevei', that the original seam was of Kaeo age, 
was laid bare during the period of pre-Kerikeri peneplaination, and that the waste from it 
formed the bed of broken fragments which was subsecjuently covered by the Kerikeri lava- 
flows. The coal is not at all friable, nor does it, in spite of its large water-content, tend to 
fall to pieces when exposed to weathering (a block containing 3 cubic feet has lain unaltered 
for several years on the banks of the stream). It is therefore impossible to say how far the 
coal forming the seam may have travelled from its original position. 

The following are analyses of the coal. No. 1 being an analysis made from samples collected 
by the writers, and No. 2 being from Hector's " Coal-deposits of New Zealand "f : — 

Fixed carbon . . 
\'olatile hydrocari)ons . . 
Water 
Ash . . 

10000 JOOOO 

C)n heating in a closed vessel the coal frits to a hard mass, and burns to a black ash. 

It has already been noted that, as insilting of the old Ngawha Lake advanced, the basin 
became an extensive swamp in which a consideral)le amomit of peat accunndated. The 
greater part of this peat has been removed by denudation, but several isolated patches, covering 



No. 1. 


So. 2. 


42-25 


49-60 


4(ill 


.35-00 


10- 14 


14-40 


1-50 


1-00 



" On the Cieology of the District surrounding Whangaroa Harbour, Mongonui County, Auckland," 
Rep. G.S.. 1890-91, No. 21 ; 1892, p. fi8. 
fRpp. O.S., 186fi, No. I, p. 44. 



96 

altogether an area of nearly 13 acres, and having an average thickness of about 12 ft., still 

survive in various parts of the lake-basin. The peat, which contains altogether 73-27 per cent. 

of water, was dried at 90° C, and then analysed, with the following result, which shows it 

to be of good quality : — 

Fixed carbon . . . . . . . . . . . . 56-38 

Volatile hydrocarbons . . . . . . . . . . 40-23 

Water .. .. .. .. Sl-82 

Ash .. il-57 



100-00 

The peat contains many trunks and l)ranches of kauri and other trees, less carbonised than 
the finer material analysed, and also small selvages of sulphur. 

Kauri-gum. 

As is not very generally recognised, kauri-gum forms the mineral product which next 
to gold has contributed most to the revenue of New Zealand. Even now it takes third place 
in importance in our annual mineral output, being exceeded by gold and coal alone.* From 
the Whangaroa Subdivision great quantities have been taken, but it is impossible to form any 
definite idea of the amount. The kauri-gum is obtained mainly from the clay lands, derived 
from the decay of the sedimentary rocks of the Kaeo and Waipapa series. Doubtless the 
greater part of the cleared land is already worked out, but considerable quantities are still 
left in the standing kauri bush, most of which is at present closed against gum-diggers. It 
is possible that a good deal of gum is left in the clay lands of the Upper Kaeo and its tributaries, 
which were cleared of Inish many years ago and are now covered with a rank growth of bracken. 

Mineral Oil. 

Petroleum has already been mentioned as occurring at the Ohaeawai Hot Springs, and 
there is a possibility of oil being extracted from the peat-deposits in the same locality. 

About a mile and a half north-west of Pungaere Settlement, on the right bank of the 
Waiarewau Stream, a series of petroliferous shales outcrop, to which attention was first directed 
by their accidental ignition. These shales, which are pale yellow-grey in colour and lie almost 
horizontally, probably represent fresh-water deposits which had accumulated in a lake-basin on 
the partially peneplained surface of Kaeo rocks prior to the outflow of the Kerikeri lavas. 
There are at least two separate beds of shale, which may be traced along the high bank of the 
stream for 3 or 4 chains. They may also occur on the left bank of the Waiarewau Stream, 
but the ground is at present completely obscured by rank vegetation and huge boulders of 
dolerite from the overlying flows. It is improbable that the beds in question extend more 
than a few chains to the east, since the headwaters of the Mangakohou Creek have cut below 
their level and therefore removed them. 

The upper bed of shale has a maximum thickness of 8 ft., as ascertained by the sinking 
of test-pits, and is of fairly uniform grade throughout, though slightly darker in colour' at 
the base owing to peaty partings. Separated from the upper bed by 5 ft. to 6 ft. of a much 
decomposed conglomerate formed of debris derived from Kaeo rocks is another layer of shale. 
This is not of so uniform a yellow colour as the upper bed, but contains several carbonaceous 
streaks and carbonised plant-remains, and has a maximum thickness of 5 ft. 8 in. It is 
underlain bv a conglomerate made up of fragments of Kaeo rocks, and containing portions''of 
tree-stems. Northwards it passes into a soft, white, gritty sandstone. 



* In 190t) the export of kauri-gum from New Zealand was 9,1.54 tons, valued at £.522,48*i. I'p to the 
end pf 1906 the total production of this mineral was 275,319 tons, valued at £13,443,017. 



97 

The following are analyses of these petroliferous shales :- 





No. 1. 


No. 2. 


No. 3. 


Fixed carbon 


4-75 


7-10 


7-47 


Volatile hydrocarbons 


. . 26-95 


30-67 


18-12 


Water . . 


1-50 


216 


Ml 


Ash .. 


. . 66-80 


59-77 


73-30 



100-00 10000 100-00 

No. 1 is a picked specimen from the upper bed. 

No. 2 is a specimen forwarded to the Colonial Analyst in 1907 by Mr. E. W. Boyd. 

No. 3 is an average sample of the two layers of shale. 

On destructive distillation No. 2 yielded 11-4 per cent, (equivalent to about 28-3 gallons 
per ton) of crude oil. Shales as low or even a little lower in oil than the highest grade (No. 2) 
are now being worked in Scotland, and might even, under very favourable circumstances, be 
mined in New Zealand. Possibly in the future the whole of the beds may be workable, under 
improved conditions of extraction. A considerable amount of test-pitting would be necessary 
to prove the extent of the shales, and this was not undertaken by the Survey. There are 
apparently several thousand tons of material available. 

Building and Cement Stones. 

It is very probable that the boulders of the Miocene breccias occurring on Whangaroa 
Harbour, which are of easy access, might be utilised for building purposes. They are, however, 
neither well jointed nor ornamental. Much more promising are the marblo-beds occurring 
near Kairauwaru Bay. Here several very irregular bands of somewhat impure greyish marble 
appear interstratified with other rocks of the Waipapa Series — argillites, quartzites, &c. The 
marble is in places distinctly argillaceous, and is cut by stringers of calcite. It could hardly 
be employed for monumental purposes, owing to the frequency of Haws, but numerous frag- 
ments up to 6 ft. or more in diameter, lying on the beach and easily handled, could well be 
made use of for building purposes. There is doubtless considerable material fit for such use 
in the several bands — in many places 6 ft. in thickness — which outcrop along the beach and 
disappear into the hillside. The marble has a specific gravity of 2-71 and a water-absorption 
of 0-24 per cent, of its weight. An analysis of a typical piece of marble will be found on 
page 45. 

Huge blocks of the older breccia (see Chapter V, page 78) strew the shore-line from Karaui 
westwards to the Sugarloaf, and fresh masses are constantly slipping from the cliflFs. The 
stone is suitable for general architectural purposes. It has a specific gravity of 2-632 and a 
water-absorption of 0-59 per cent. The exposed nature of the part of the coast on which 
this rock occurs would, unfortunately, render shipment a rather difficult* and intermittent 
operation. An analysis of this stone is given on page 79. 

Limestone occurs in the Kaeo rocks at several places, especially in the Waikaraka, Pirau, 
and Waitangi streams. Analyses of these rocks will be found on page 53. That from the 
Waikaraka seems sufficiently pure to warrant experiments as to its value for the production 
of hydraulic cement and for other purposes. Its rather remote position, however, robs it of 
much economic value at the present time. For further description of the limestones, see 
pages 53 and 54. 

Mineral Waters. 

The hot waters of the Ohaeawai springs are held in high repute by the Maoris, who ascribe 
to them great therapeutic powers. For descriptions of the springs, see pages 37-39. 
7 — Whangaroa. 



98 

Sulphur. 

The water of Waiparaheka Pond is, as already remarked, milky in colour from the abund- 
ance of " flowers of sulphur." The mud occurring round the margin of the pond was shown 
bv analysis to contain 66-64 per cent, of sulphur, also 0-40 per cent, of antimonv-trisulphide, 
but no trace of other metals. It is possible that, if the pond were drained, sulphur-deposits 
of economic value might be uncovered. 

Sulphur is also probably accumulating in the Waitetera and Little Waitetera ponds, 
in the sulphur pond on a tributary of the Tuwhakino Stream, and in the ponds on a tributary 
of the Mangatawai Stream. Small deposits of sulphur are to be found round the many gas 
vents in the Ngawha Lake basin and in the neighbourhood of Putahi Hill. 



99 



APPENDICES. 



APPENDIX A. 

List of Minerals found in the Whangaroa Subdivision, Mode of Occurrence, etc.* 



HineraL 



Mode of Occurrence in the Subdivision. 



Clupf Localities. 



Authority. 



Albite . . 
Alam 

Andesine 
Anorthite 
Apatite . . 

Aragonite 
Augite . . 

Bomite . . 

Calcite . . 
Chalcedonic quartz 

Chalcocite 
Chalcopyrite 

Chlorite .. 

Cinnabar 

Coal 



In Wairakau rocks. 
In sintery sands 



Rare 



In Wairakau rotks. Rare 
In igneous rocks of various ages 
Occasionally in igneous rocks 
various ages 



of 



Common in igneous rock-s of various 



Rare aa crusts and patches in copper- 
ores 

In Waipapa and Kaeo rocks 

In Kaeo rocks and associated with 
cinnabar 

Possibly as crusts on copper-ores . . 

Fin'> grains mixed with iron-sulphides 
in copper-ore 

In granitic pebbles and associated 
with copper-ore 

In sintery sands and spring deposits 

As loose lumps of pitch-coal from 
Kaeo (?) rocks, and as lignite in 
younger rocks 



Coppei (native) . . 


Rare selvages in clav gouge 


Covellite.. 


Rare as crusta and patches in copper- 




ores 


Diallage 
Galena . . 


In gabbro 

Waipapa rocks, near andesite dykes 


Glauconite 


Graensands of Kaeo Series 


Gold . . 


In small amounts in veins and im- 


Hiematite 


pregnations 


Halloysite 




Hornblende 


In granitic pebbles and fairly abundr 
ant in Wairakau rocks 


Hvpersthene 


Fairly abundant in Wairakau tocks 


Idrialite 


As rounded grains in alluvium 


Ilmenite 


In igneous rocks of doubtful age 


Iron-pvrites 


In rocks of various series . . 


Kauri-gum (ambrite) 
Labradorite 


As loose lumps in soil and subsoil . . 
In rocks of various series . . 


Liraonite 


Bog iron-ore 


Magnetite 
Malachite 
Manganite 


In Kerikeri rocks 

Occasionally as crusts on copper-ores 

In Kaeo rocks . . 



Near Whangaroa Harbour. 
No. 5 area, Ohaeawai Hot 

Springs. 
Near Whangaroa Harbour. 
Throughout the subdivision. 



Whangaroa North 
Throughout the subdivision. 

Pupuke Copper-fiBld. 

Throughout the subdivision. 
Kerikeri River and Ngawha 

Lake basin. 
Pupuke Copi>er- field. 



Pa Island and Whangaroa 

Harbour. 
Near Huiiv Hill : Ngawha 

Lake basin. 
Upokorau watershed. (See 

also end of Chapter IV.) 

No. 2 drive, Hare-Ratjen 
Claim, Puj)uke Copper- 
field. 

Pupuke Copper- field. 

Whakateterckia River, &c. 
West of Tupo Bay. 
Widely distributed. 
Kaeo, Waipapa, and igneouB 

rocks. 
Whangaroa. 
VMiangaroa Harbour 
Whangaroa Harbour and 

Pa Island. 
Near Whangaroa Harbour. 
Ohaeawai Hot Springs 
C!oast north of Whangaroa 

Heads. 
Throughout the subdivision. 
(Generally distributed. 
Throughout the subdivision. 
In depressions on surface of 

Kerikeri rooks. 
Generally dLstributed. 
Pupuke Copper-field. 
Branch, Shepherd Creek. 



Cox (2), p. 383. 



Cox(l), p. 437. 
Cox(2), p. 401. 



Hector (3), p. 112. 



• In those cases in which the mineral was not found by the writers of this bulletin the authority is quoted in the la«t 
column. The number immediatelv after the name refers to the following list ■ 1. " \otes on the Mineralogy of New Zealand," 
by S. H. Cox, Trans., vol. .\iv, 18«1. 2. " Notes on the Mineralogy nf Xew Zealand." bv S. H. Cox, Trans., Tol. xv, 1882. 
3. "Minerals of New Zealand," by Sir J. Hector, Rep. G.S. during 1890-91, No. 21, 1892, p. 104. 4. "On the Occurrence 
of Native Mercury near Pakaraka. Bay of Inlands," by F. W. Hutton, Trans., vol. iil, 1870, p. 252. 



luu 



List of Minerals found in the Whangaroa Subdivision, etc. — continued. 



MineiaL 



Marcasite 

Mercury (native) . . 

Metacinnabarite . . 

Oligoclase 

Olivine . . 

Opal 

Orthoclase 

Petroleum 

Psilomelane 

Pyrite (see Iron-py 

rites). 
Quartz . . 



Mode of Occurrence in the Subdivison. 



Chief Localities. 



Anthoiity. 



Serpentine 

Siderite . . 
Sillimanite 

Silver 

Sphalerite 

Stibnite . . 
Stilbite . . 
Sulphur . . 

Zoisite 



In rocks of various ages, but especi- 
ally Kaeo 

Globules in carbonaceous sands and 
clays 

Associated with cinnabar 

In post-Waipai)a diorites 

In igneous rocks of various ages 

In Wairakau breccias 

In granitic pebbles 

Associated with hot springs in post- 
Miocene strata 

In small veins and incrustations in 
Waipapa, Kaeo, and later deposits 



In rocks of several series . . 
Crusts on sinter. . 

In igneous Waipapa rocks as result of 

alteration of olivine 
In C'retaceo-Tertiary formation 
In schistose rocks 

In small amounts in veins and im- 
pregnations 

In Waipai>a rocks, near andesitic 
dykes 

Associated with cinnabar 

In igneous rocks of doubtful age . . 

In Ngawha Lake beds, deposited 
round gas-vents and ponds 

In schistose rocks 



Throughout the subdivision. 

No. 3 area, Ohaeawai Hot 

Springs. 
Ngawha Lake beds 
North end of Frear Bay. 
Generally distributed. 
Whangaroa Harbour. 
Pa Island and Whangaroa 

Harbour. 
Ohaeawai. 

Generally distributed. 



No. 5 area, Ohaeawai Hot 

Springs. 
Waipapa River, &c. 

Whangaroa 

Between Taupo and Camp 

bays. 
Kaeo, W'aipapa, and igneous 

rocks. 
West of Tupo Bay. 

Ngawha Lake basin. 
Near Karaui Point. 
Ngawha Lake beds. 

Between Tau]io and Camp 
bays. 



Hutton (4). 



Cox(l), p. 439 



APPENDIX B. 
Glossary .of Scientific and Mining Terms used in this Bulletin. 

[Note. — -The terms used in the sections dealing with detailed petrology and palaeontology will 
not be found in this glossary unless they occur also in the more general parts of the bulletin.] 

Acidic Igneous Rocks. — Those containing 65 per cent, or more of silica — e.g., granite. 

Adit. — In mining, a horizontal passage opening on the surface. 

Aggrading. — The process of levelhng-up of any physical feature — a river-bed, tidal flat, &c. — by 

the deposition of detrital material. 
Algce. — Simple vegetable organisms consisting of one or more cells containing green matter 

(chlorophyll) — e.g., seaweeds, the green scum found in pools. 
Alkalis. — Chemical substances, such as potash, which neutralise, and form salts with, acids. 
Alum. — A sulphate of aluminium and some other element, characterized by its astringency. 
Aluminous. — Containing a considerable percentage of alumina, the essential constituent of 

clay. 
Andesite. — A volcanic rock, usually dark in colour, and containing, as a rule, between 55 

and 60 per cent, of silica. 
Anticlinorium. — A considerable area of strata bent into a number of great arches (anticlines), 

separated by lesser troughs (synclines). 
Arenaceous. — Sandy. 
Argillite. — A compact, fine-grained rock, originally a clay which has been hardened by pressure 

or heat or impregnation with silica or some other cementing substance, or a combination 

of these agencies. 



101 

Basalt. — A dark compact volcanic rock, usually containing about 50 per cent, of silica. 

Basic Igneous Rocks. — Those containing less than 55 per cent, of silica. 

Beheaded. — A term applied in physiography to streams the upper waters of which have been 
diverted into (" captured by ") another stream of greater erosive power. 

Betrunked.—A term applied in physiography to streams which formerly discharged through 
a single mouth, but have now become separated by the sinking of the land atidconse(|uent 
advance of the sea up the main valley. 

Bituytunous. Containing a perceptil)lc amount of liituiiicii or mineral jiitch. 

Bog Iron-ore, in Liiiionitc. — A hydrous oxide of iron, iilack or dnrk red in colour, formed in 
swamps partly by the ;iction of plants. 

Bornitr. — A purplish-brown sulpliide of copper and iron (('u.jFeS.,). It is often called ' horse- 
flesh " ore. 

Breccia. — Unless (juaiified. this term indicates a rock whicli owes its origin to the laying- 
down, usiuilly under watei. of moic or le.ss angular fragments of some pre-existing rock. 

Breccialed. — A term applied to a rock which after its formation has, owing to earth-movements, 
been broken up iti situ into angular fragments. 

Calcareous. — Containing a noticeable amount of lime. 

Calcile. — Carbonate of lime. 

Carbonaceous. — Containing a noticeable amount of carbon. 

CAo/cerfort/c— Like chalcedony, which is a semi-transparent variety of ijuartz with wax-like 

lustre. 
Chalcocite. — A blackish lead-grey sulphide of copper (CujS). 
Chalcopyrite. — A brassy yellow sulphide of copper and iron (CuFeSj). 
Chert. — A rock formed mainly of silica, but differing from a quartzite in that separate grains 

of quartz cannot be distinguished. All gradations i)etween cherts and (|uartzites occur. 
Chlorite. — A soft greenish mineral — a silicate of aluminium with iron and magnesium. 
Cinnabar {Sulphide of Mercury). — A vermilion-coloured mineral from which most of the mercury 

of commerce is obtained. 
Claystone. — A fine-grained rock formed by the consolidation of clay, not so compacted as an 

argillite. 
Concretionary. — Containing concretions - i.e., ball-like masses of calcite, silica, &<■., wiiich 

have formed since the deposition of the rock which contains them. 
Canglotnerate. — A rock fornunl wholly or largely of rounded pebbles. 
Covellite.—Xn indigo-blue coloured sulphide of copper (CuS). 
Cretaa'D-Tertiary.—Thv name applied by Hector to a series of rocks, the deposition of which 

he supposed to have extended from Cretaceous tim(>s tf) Tertiary. 
Cretaceous. — The youngest of the three groat systems into which Mesozoic rocks are divided. 
Cupriferous. — Containing copper. 

Debris (French for waste material). — A general term applied to the miscellaneous material^ — 

gravel, silt. &c.-— formed by the i)reakiTit;-down of rocks by various agencies. 
Denudation. — The wearing-down of the land by various agencies. 

Diabafie. — An igneous rock similar to basalt in chemical composition, but coarser in texture. 
Dip.— The inclination of a stratified Vied or of any other surface from the horizontal. .\ bed 

is said to dip to that point of the compass to which it slopes downwards. 
Dismembered. — A term applied in physiography to a river-system wliich h;is been lietrnnked 

iq.V.). 
Dolerile. — A dark-coloured volcanic rock of the same chemical composition as Imsalt. but 

distinguished from it by certain microscopic peculiarities. 
Dunes. — Sand -hills. 
Dyke. — A more or less vertical wall of volcanic rock which has been intruded into previously 

formed rocks. 

Ecological. — Having to do with the relationships and nmtual influence on one another of plants 
or animals, and with the efiect on plants or animals of the conditions in which they are 
placed. 

Effluent. —Flowing out of. 

8 — \Vh»ngaroa. 



102 

Effusive. — Volcanic flow rocks — i.e., igneous rocks which have appeared at the surface in the 

form of lava-flows. 
Epiphyte. — A plant which is rooted on another plant, and is not connected ^\^th the ground. 

Its roots obtain their nourishment from the leaf-mould lodging on the supporting plant, 

and do not penetrate into its living tissues in search of food. 
Epiphytic. — Having the characters of an epiphyte. 
Erosion. — The wearing-away of the land by various agencies, such as running-water, the wind, 

the sea. 

Faulting. — When a series of rocks is traversed by a fissure, along one side of which the rocks 
have sunk relatively to the other, the series is said to be faulted. The fissure is called a 
fault. 

Feldspars. — The most important of the minerals that make up the igneous rocks. Are gene- 
rally whitish or pinkish in colour, nearly as hard as quartz, and form plate-Uke crystals, 
varying in size from microscopic dimensions to an inch or more in length. They are 
siUcates of alumina, with which are combined varying quantities of sihcates of soda, 
potash, and Hme. 

Floater. — A boulder of ore separated from the parent reef. 

Flowers of Sulphur. — Sulphur in exceedingly fine particles. 

Fluviatile. — Having to do with rivers. 

Fossiliferous. — Containing fossils — i.e., entombed remains of plants or animals. 

Foot-wall. — The underwall of a vein. 

Fumarole. — An opening in the earth, from which heated gases escape. 

Fumarolic. — Having to do with fumaroles. 

Gabbro. — An igneous rock, similar in composition to a diabase, but coarser in texture. 

Galena. — The lead-grey sulphide of lead : its principal ore. 

Gangue. — The worthless material of a vein, in which the ore is embedded. 

Gouge. — Soft clayey material, often found alongside a vein. 

Gossan. — The outcrop of a lode. Usually rusty in colour, owing to the oxidation of iron- 

compoimds. 
Grauwacke. — A compact sedimentary rock, coarser in grain than an argilUte, and largely made 

up of grains of quartz and feldspar. 
Grit. A coarse sandstone, the constituent fragments of which are not so rounded as in an 

ordinary sandstone. 

Hanging-wall. — The upper wall of a vein. 

Horizon. — In geology, signifies the level at which any particular bed in a series occurs. 

Humus. — -Black soil, rich in organic matter, formed by the long-continued growth and decay 

of living organisms. 
Hydrocarbons. — Compounds of hydrogen and carbon. Marsh-gas is a famiUar example. 
Hydrothermal. — Having to do with hot springs. 
Hydrous. — A chemical compound containing water as an essential constituent. 

Igneous RocJcs. — Rocks which have soUdified from a molten state. The various kinds of lavas 
which were poured out at the surface, and the coarser-grained rocks, such as granite, 
which soUdified underground, are all examples of igneous rocks. 

Insequent. — A term appUed to a stream or system of drainage which has cut down into the 
country independently of the arrangement of the rocks which comprise it. 

Insilting. — The filUng-up of any depression by the deposition of silt, sand, gravel, &c. 

Iron-disulphide. — Iron-pyrites. 

Jasperoid.—Like jasper, an opaque, red variety of silica. 

Jointed. — Joints are planes of division which are distinct from planes of stratification, and 

which have been produced subsequently to the formation of the rocks, and not, Uke planes 

of stratification, during their formation. 
Jurassic. — The middle one of the three great systems into which rocks of Mesozoic age are 

divided. 



108 

Lacustrine. — Belonging to, or having to do with, or formed in lakes. 

Leach. — To dissolve out. 

Lensoid. — Lens-shaped, thinning out in all directions. 

Lignite. — An inferior coal, in which the woody structure can sometimes still be seen. 

Limonite. — An oxide of iron. 

Lithological. — Having to do with the structure and constitution of rocks. 

Malachite. — A green-coloured carbonate of copper. 

Mammillary. — Covered with small rounded protuberances. 

Marcasite. — Iron-disulphide like pyrite, but not crystaUizing in the same form, and more easily 
decomposed. 

Mesa. — A small fiat-topped area surrounded by steep sides and standing above the genera! 
level of the surrounding country. 

Mesozoic. — -The middle one of the three main eras into wliich geological time is divided. 

Metacinnabarite. — Sulphide of mercury, but, unlike cinnabar, is black and not red. 

Metasomatically . — Having to do with metasomatism, which may be defined as the process 
by which original minerals are partly or wholly altered into other minerals, or are replaced 
by other minerals, or are recrystalhzed, with or witliout mineral changes, or one or more 
of these together. 

Methane. — An inflanmiable gas, usually known as marsh-gas. 

Mincra/of/ica/.— Having to do with minerals. 

Miocene. — The youngest but one of the four series into which Tertiary rocks (excluding 
Pleistocene and Recent) are divided. 

Monadnock. — ^An isolated remnant of hard rock which has resisted the processes of erosion 
more than the surrounding rocks, and so stands above the ordinary level when the sur- 
rounding country has been reduced to a peneplain (q.i\). 

Neck.~The central pipe or vent of a volcano wliich has become filled with a plug of solid lava 
or with blocks of lava, and has remained, owing to its more resistant nature, when the 
rest of the cone was removed by denudation. 

Obsequent. — A physiographic term apphed to drainage-channels in which from some cause 
the water now flows in the opposite direction to its original course. 

Obsidian. — Volcanic glass, formed by the very rapid cooling of an acid volcanic rock (q.v.). 

Ochre. — Hydrated iron-oxide. Differs from bog iron-ore or hmonite (q.v.) in being soft and 
earthy. 

Opal. — Amorphous ami hydrous silica, which has no cry.stalline structure Uke quartz proper. 

Outlier. — An isolated outcrop of a rock separated from [rocksjof the same age by an older 
series. 

PaloBontological. — Having to do with palaeontology, the study of fossils. 

Palceozoic. — The oldest of the three main eras into which geological time is divided. 

Panicle.— A. botanical name for a loose, irregularly branched grouping of flowers or inflor- 
escence. The flowers of the bush-lawyer or blackberry are arranged in panicles. 

Panning. — The separating of a mineral or metal (usually gold) from sand, &c., by washing in 
a kind of pan. 

Peneplain. — If the various erosive agencies act uninterrupted by earth-movements, they ulti- 
mately reduce the surface of the land to an almost level surface ; such a surface is called 
a peneplain. 

Petroliferous. — Bearing mineral oil. 

Pelrological. — Having to do with the structure of rocks and the character of their constituent 
nunerals. 

Pilch-coal. — A coal containing 10 to 20 per cent, of water, which burns freely, and does not des- 
sicate nor absorb water on exposure. 

Psilomdane. — A black mineral, which is essentially an oxide of manganese. 

Pneumatophores. — Specialised roots of the mangroves, which grow upward and form a channel 
by which the air required by the roots embedded in the mud is obtained. 



104 

Puggy. — Clay-like. 

Puy. — A small cone of volcanic material, mainly scoria. 

Pyrite. — Mundic or iron-pyrites. The yellowish disulphide of iron. 

Pyroclastic. — A sedimentary rock composed of scoriae or ashes of volcanic origin. 

Quartz. — The crystalline form of silica. 
Quartzite. — An exceedingly indurated sandstone. 

Rabbling. — Stimng. 

Realgar. — The red or orange-yellow coloured sulphide of arsenic. 

Regional Uplift. — The upraising of the land over a wide area, as opposed to the local disturb- 
ances of level caused by the faults described in this bulletin. 

Retort. — A vessel of glass, iron, or other heat-resisting material in which substances are 
decomposed by heat applied to the outside. 

Salivation. — An excessive secretion of saliva, which is one of the symptoms of excessive 

absorption of mercury into the system. 
Schistose. — Schistose rocks are those which, owing to the roughly parallel arrangement of 

their constituent minerals, tend to spUt into rather irregular flat flakes. 
Scoria Cones. — See " Puy." Scorife are rough, irregular, clinker-like fragments with very 

vesicular structure (q.v.). 
Sedimentary Rocks are those stratified rocks {q.v.) which have been deposited under water. 
Selvage. — A thin border or edging. The term is often applied to a layer of clay found on the 

walls of a lode. 
Semi-basic Igneous Rocks have a silica-percentage approaching that of basic igneous rocks 

—i.e., contain usually about 55 per cent, of siUca. 
Serpentine. — Strictly speaking, a rock composed mainly of a hydrated sihcate of magnesia. 
Shale. — A consolidated clay, which spHts easily along the lines of bedding. 
Silica. — Oxide of siHcon. Quartz and opal are different forms of silica. 
Siliceous. — Containing a noticeable amount of silica. 
Silicified. — Impregnated with silica. 

Sinterised. — A term applied to strata which are more or less impregnated with sinter. 
Sinters. — Deposits, most frequently either siliceous or calcareous, formed round mineral springs 

as a result of the evaporation or cooling of the mineralised water. 
Skerry. — Similar to stack, but more irregular and pinnacle-shaped. 
Slickensided. — A term applied to the rocks forming the faces of a fault, when, as is often the 

case, they are scratched and even polished by friction. 
Solfatara. — A vent from which hydrogen-sulphide and other gases are given off. 
Solfataric. — Having to do with solfataras. 

Sphalerite. — Zinc-sulphide, usually yellow in colour, and more or less transparent. 
Stack. — A more or less block-shaped rock lying a little distance from the mainland and rising 

precipitously some height above the sea. 
Stihnite. — The lead-coloured sulphide of antimony. 
Stratification. — The arrangement of rocks in distinct strata or beds. 
Stratified Rocks. — Those which exhibit stratification. 
Stratigraphi^al. — Having to do with stratigraphy. 

Stratigraphy. — That part of geology which deals with the arrangement of the rocks of th( 
'"^"^earth's crust according to the order of their formation. 
Strike.— The line followed by the edges of inclined beds or of a fault-plane on a perfectly flat 

surface. Well seen sometimes on a flat sea-beach. The direction of strike is always at 

right-angles to the direction of dip (q.v.). 
Stringer. — A small parting of quartz following an irregular course through the rock. 
Syncline. — Strata bent so as to form a trough. 

Talus. — The debris {q.v.) accumulating at the foot of a slope. 

Tectonic. — Having to do with the structure of the crust of the earth. 

Tertiary. — The latest of the three great eras into which geological time is divided. 

Therapeutic. — Healing. 



105 

Throw of Fault. — The vertical displacement caused by a fault {q.v.). 

Topography. — The study of the surface features of any area. 

Transport. — A term used in physiography to indicate the moving of material from one place 

to another by water or other agencies. 
Tufaceous. — Having the characteristics of a tuff. 
Tuff. — A sedimentary rock formed of fine fragments of volcanic rock. 

Unconformity.— When one set of strata is found to be deposited on the upturned and denuded 
edges of another series there is said to be an unconformity between the two series. An 
unconformity indicates a break in time between the deposition of the two beds, during 
which the older series was upheaved and denuded. 

Upthrow. — Refers to the extent of vertical movement when the strata on one side of a fault 
appear to have been raised relatively to those on the other. The term "downthrow" is 
used in a corresponding way. 

Vesicular. — Containing vesicles — i.e., small hollow cavities. Nesicnlar .stvuctiive is character- 
istic of scoriaceous lavas. 
I ' ulcanism . ^ Volca nic action . 

W'alct -absorption. — The total amount of watci uhirli any paiticiilur varii-t}' of stone will 
absorb. The smaller thi' amount the more valuable the stone is for building (other 
things being e<|ual). 

Winze. In mining, a shaft sunk within the mine from a level. 

Xerophylic. — Having the characteristics of a xerophyte^j.c, a plant adapted by its structure 
for livinji in drv situations. 



IN-DEX 



Acidic igneous rocks 



Page 



20, 21, 25, 27, 63, 72, 73 



Awahei Creek 
Awaiti Creek 



Page 

48, 53 

52, 82, 83, 86 



Adams, J. 

Admiralty chart 

Agnihis auMralis 

Agglomerate 

Agricultural Department . . 

Air .. 

Akaterere 

Akeake 

Albite . . 

Algae . . 

Alkalis, sulphides of 

Alluvial flats 

„ Hora of 

AUeuoamia macrophylla 
Alteration of igneous rocks 

„ Waipapa rocks 

Alum . . 
Ammonites 
Amuri Series 
Amusaium zitteli 
Amygdules 



hummock-shaped hills of 73 

..69 

..29 

5, 6, 59 

..27 

. . 6, 53 

34, 35, 39 

. . 27, 65, 67, 69 

6 

67 

37 

. . 87 

21, 28, 29, 60, 61 



5 

64, 76, 78, 79 

23, 45 

.. 92 

..56,57 

12 

.. 56 

.. 64 



Analyses 6, 7, 8, 9, 10, 34. 35, 36, 37. 38, 30, 43, 
44, 45, 51, 52, 53, 54, 55, .-)<), 60, 61, 
65, 66, 68, 71, 73, 75, 77. 78, 79, 81, 
83, 84, 85, 86, 90, 91. 92, 93, 94, 95, 
96, 97 
Anas supercilioaa .. .. 3 

Andesine . . . . . . 67, 74, 76, 77 

Andesite 22, 44, 52,. 66, 67, 68, 70, 74, 75, 76, 95 
Anguilla uucMandii .. .. .. 3 

Anorthite . . . . . . 67, 70, 74, 77 

A nthozoa . . . . . . 56 

Anticlinorium . . . . 42 

Apatite . . . . 67 

Apteryx australis 3 

A rdea sacra . . 3 

Areii de-scribe<l in bulletin . . 2 

Areas, s)iecia.l, at Ohaeawai Hot Springs {see 

Ohaeawai). 
Ar«illite 20. 21, 41, 43, 44, 45, 50, 67. 94, 97 

Aristoteha racemosa .5 



Arotoro Creek . . 
Arripis tratta 
Arrow Rock 
Arthropodium cirrhatum 
Ash . . 
Assays . . 
Astelia banksii 

,, solnndri 

„ trirurva 
Aston, B. C. 



..48,71 

17 

..31,64 

4 

59, 61, 66, 71, 95, 96, 97 

82, 83, 84, 85, 86, 90, 91, 92. 93 

4 
5 
5 
. . 6, 7, 8, 9, 53 
Atiamuri, reported megalithic remains near 15 

Atkinson . . . . . . . . 71 



Auckland 

,, Museum 

., volcanoes 
Augite 

,, -andesite . . 
,, -hypersthene-andesite 
Austrians on gumfields 
Authigenous constituents 
Avicennia officinalis 



. . 17, 68, 75, 95 

56, 57 

20 

.50, 64. 66. 67, 69, 70, 74 

66, 67, 68, 70, 76, 77, 78 

. . 66 

16 

..50 

4 



B. 

Barrier be<iches 

Basalt . . 

Ba.^anitos 

Basic lava-ilows 

Basin:^, fresh-water (.■.ee also Ngawiiu)' 

Bay of Islands . . . . 15, 17, 

Becker, G. F. . . 

Beesou's Island Series 

Behi'adiug of streams 

Reilschmiedia tarairi 

,, lawa 

Betemnites 
Bell Creek 
Bell, J. M. 
Bell, R. 

Betrunking of streams 
Billings Creek . . 
Bittern 
Bituminous matter (see also Oil) . . 

„ ])revents colleotion of 

cury 
Block-faulting 
Blue heron 

Bog-iron ore (see also Iron-ore) 
Bordered i>its 
Bore-hole 
Bomite 

Botaiirus pceciloptilus 
Boulders . . . . 29, 62, 

Boyd. E. W. .. 
" Boyd " massacre 
Braehy glottis repanda 
Bracken fern 
Bramble 
Breccia 



. . 20, 21 
46, 
78, 

Breccia dyko 

Brecciation 

Brett, Cape 

Briar . . 

" Bride Cake " . . 

Broun . . 

Browni, .1. M. . . 

Building-stones . . 

BuUer, W. 

Bullocks for transporting logs 

Bush-felling 

Bush-lawj'er 

Butter-factory, Oliaeawai 



22, 23. 2(i, 27, 
1, 63. 64, (1.5, 
5, 90, 97 



22, 



.. 29 
74, 77 
.. 74 
, 20, 21 
.. 33 
42, 74, 75 

13, 87 
67, 69 

.. 31 

4,5, 6 

5 

.. 57 

66, 67 

14 

18, 84 

29 

47, 65, 70 

3 

23, 87 

mer- 

88, 89 

24 

3 

36 

68 

.. 91 

80, 83, 85 

3 

66, 69, 70 

.. 97 

.. 15 

4 

4, 40, 96 

6 

30, 31, 45, 

69, 72, 75, 

.. 66 

41, 44, 45 

46 

5 

..66,67 

87 

14, 15 
80, 97 

3 
16 

15, 16 

5 
.. 17 



C. 

Cabbage- tree . . . . . . . . 5 

Calcite 45, 51, 54, 57. 64. 76, 77, 79. 81, 85, 95, 97 

Camel, Mount . . 2 

Camp Bay 29, 42 

Campbell . . 67 

Camp Creek . . . . 76 



108 











Page 


Capacity for holding water 








6, 7, 9 


Capillarity 








6,7,9 


Cattle, wild 








3 


Cavalli Islands . . 






. 


1 


Cement-stoues . . 








80, 97 


Cephalopoda 








56, 57 


Chalcedonic quartz 






43, 


67, 87 


Chalcococcyx lucidus 








3 


Chalcocite 








80, 83 


:!halcopyrite .. .. 80, 81, 


53, 


84, 


85, 86 


Cheeseman, T. F. 








3 


Chenopodiaeece . . 








10 


Chenopodium glaveum 








4 


Chert . . 






20, 


41,43 


Chione stutchburyi 








. 62 


Chlorite '. . . . 43, 


50 


64 


76 


77,81 


Cinnabar . . . . 23 


38 


87 


90 


91,92 


Gladium glomeratum 








4 


,, junceum 








4 


,, feretifolium 








4 


Clay 








94, 95 


Clay land 








8 


Clays, lacustrine .. 21,59, 


87 


88 


90 


91,92 


Claystones 20, 2 1 . 40, 47, 48, 49 


51 


52 


80 


82,83 


Clematis indivisa 








4 


Cliff-retreat 








29, 33 


Climate of North Auckland 








10, 11 


Coach-roads 








17 


Coal .. .. .. 12, 


21, 


m 


80 


95, 96 


Coal Creek 








71,95 


Coalfields, age of 








58 


('oal, output of . . 








96 


Coal Point 








67 


Coastal exposure, Waipapa Series 








42 


,, type of vegetation 








3,4 


Coast-line produced by subsidence 








22 


Cold-spring deposits 








60,61 


Colensoa physaloides 








5 


Colonial Exploration Company 








18 


Columella 








56 


Columnar jointing of lava 








31 


Common salt 








74 


Common springs 








36 


Communication, means of 








17 


Concentric arrangement of feldspai 


•s 






64 


Concretionary shales (see Shales). 










Concretions 




51, 


54, 


56,57 


Condensing-cham.b6rs 




18 


88, 


89,90 


Cone Rock 




3, 


76, 


79, 93 


Cones of lat«r basic volcanics 








27 


Cones, volcanic (see also Puys) 








74 


Conifer 








68 


Conglomerate 20, 21, 46, 47, 48, 


49 


50 


55 


58, 96 


Contact metamorphism . . 








77,78 


Copeland 






44, 


71.94 


Copper lodes and ores 2, 52, 77, 


78, 


80- 


-87, 


93,94 


„ native . . 






54, 


80,81 


Corallum 








56 


Cordyline australis 








5 


Coriaria rusci folia 








5,40 


Coromandel Peninsula 








20,68 


,, Subdivision . . 








46 


Corynocarpus Imvigata 








4 


Covellite 








80,83 


Cox, S. H. 








12,37 


Crater . . 








27,74 


Crayfish 








3, 17 


Cretaceo-Tertiary rocks . . 13, 


21, 


49 


57, 


58, 95 


Cretaceous fossils 








58 


rocks 








21,45 


Cruciferm 








10 


Crystalline limestone (see Marble). 










Cupriferous lodes and ores (see Cop 


l)ei 


). 






„ solutions 








23,81 


Cyathodes acerosa 








4 



D. 



Page 



hannels 



Dacite 

Dacrydium cupressinum . . 
„ kirkii 

Dairying 

Daisy, native 

Dams . . 

Danthonia 

„ pilosa 

,, semiannularis . . 

Darwin, C 

Davis . . 

Debris 

Deflection of streams 

Dejiression, effects of, on drainage 
,, ., shore-line 

Desmoceras . . , 

Devonian rocks 

Diabase 

Diallage 

Dickeson, G. F. 

Dicotyledonous ]>lant-remaius 

Dieffenbach, E. 

Diorite 

Diplodon menziesi 

Discharge of main streams 

Dislocation (see Faulting). 

Dodonaa viscosa 

Dolerites 

Doleritic flows (see also Kerikeri Series) 

20, 22, 67, 80 

Doleritic land . . . . . . . . 8 

Domain Road . . . . . . . . 48 

Dominion Museum . . . . . . 67 

Doubtful age, rocks of (see also Igneous rocks) 21 

Dracophyllum latifolium . . . . . . 5 

,, urvilleanum . . . . 4 

Drainage-capture . . . . . . 33 

,, channels of subdivision . . 32, 33 

,, of Ngawha Lake . . . . 58 

,, of ponds . . . . . . 62 

Dredging, possibility of. at Ohaeawai Hot 
Springs . . . . . . . . 92 

Drives . . . . 82, 83, 84, 85, 86, 90, 93 

Driving timber, method of . . . . 16 

,, influence on stream-beds of 40 



69,76 

.. 5, 6 

. . 6, 59 

8, 16, 17 

4 

16,93 

17 

4 

4 

..12,13 

.. 57 

23,62 

.. 29 

32 

29 

56,57 

21 

76, 80, 81, 86 

.. 77 

.. 18 

.. 57 

12 

44, 76, 77 

3 

.. 33 

6 
46, 70, 71, 72, 79 



Drosera aurictdata 
,, binata . . 
Drowned river-valleys 
Duck, wild 
Dunedin 
Dunes . . 
Dykes, basic and semi-basic 



Dysoxylum spectabile 



4 

4 

22, 29, 31 

3 

. . 74 

28, 29 

20,21,22,30,44,45 

52, 65-67, 69, 75, 

76, 77, 78, 79, 93 

. . 4, 5 



E. 



Earl, F. . . . . . . . . 18 

Economic reasons for work in Hokianga 
Division . . . . . . . . 2 

Eel .. .. .. .. .. 3 

Effusives (see Lava-flows). 

Elatostemma rugosum . . . . . . 5 

Elevation, recent . . . . 12, 22 

English and Australasian Smelting Company 84 

Entelea arborescens 

Eocene rocks 

Epacris pavciflora 

Erosion, marine and subaerial, contrasted 

Eruptions, Miocene, paroxysmal . . 

Estuarlne deposits 



4 
21 

4 
30 
69 
60, 62 



Explosion-craters 22, 24, 28, 33, 38, 59, 88, 91 



109 



J". Page 

:{(), 4<), t)5, 6(>, 07, 68 

:5 
22. 23, 24, 31. 41, 42. 47, «!». 72. 78. 
79. 80. 81. 83, 84. 85, 80 

. . 2, 3 
44, .50. ol, (J4. t)(i, 70, 73. 74, 7o, 7t). 
77. 78. 7!t 
Ferguson I'oiiit . . . . . . 51 

Fergiisioii's Mining aiul Smelting Companv 
(Limited) . . . . 18, 52. 7<i, 81. "85, 8(> 

Forro-niagnesian niincnils .")0, (17, 73. 75. 7( 
Ferrous-cinbonntc 



False Head 

Fantail 

Faulting 

Fauna 
Felds)>ar 



1 1. 



(8 
!»4 
1)8 
50 
89. 90 
21 
32 



34. 



Feiu-ini|iitw.si()ii.-i 

Fiji, granite in . . 

F^i Iters 

Firestone 

Fishing . . Hi, 17. 

Fi.ssure-eniptions 

,, -veins 
Flat Island 31. 42, till. 70. 71. 

„ Rock 
Flats, low-lying alluvial . . 
Flax. Sow Zealand 

., -milling 
Floaters 
Flora . . 
Flounder 

■■ Flouring " of mercury . . 
Flowers of sul|iliur 
Flow-rocks. (iSV* l>jk\a-tlows.) 
,. -structure 
Fluviatile deposits 
Fluvio-marine deposits 
Flux, siliceous . . 
Foci of Kerikeri eniptions 

,, Wairakaii eni|)tions 
Folding 
Foley 

,. CVeek 
Foot-wall 

F"os.siIs . . 49. 

Foxglove 
Fracturing 
Fraser, ( '. 
Frear Bav 
Fred Creek 
Frenchman Creek 
Fresh-water tish 
Freycimtia banhiil 
Friction breccia . . 
Frog .. 

Fiichfia KxcorticHtii 
Funuirolic activity 
Fumes of mercury 

Furnace of raercury-roductiou works 
Fiixanv'' runningkatnt 



U. 



Gabbro .. .. .5.5,76,77.80,81 

Gahnia hnbtn<>carp<t . . . . 5 

Oalnxins atteniiatiix . . . . . . 3 

,, jasciatwi . . . . . . 3 

Galena . . . . . . . . »3, 99 

Gangue-minerals . . . . 81 

Gases evolved from decomposition in mud . . 37 

Gastropoda . . . . 56, 57 

Gas-vents . . 34, 35, 98 

(ienioxtwmt ligtuitrijolium . . . . . . 5 

Gentle Creek . . . . . . 86 

Geological history of subdivision . . 21, 22 

Gerygone flaihentris . . . . . . 3 

Geyser-action . . . . . . 33, 88 



81 



31 
25 

. 4, (i 

1.5. 17 

8.3 

. 3-5 
17 
89 

3.5, 98 

79 

21, 60, 61. 62 

21. 60. 62 

86 

79 

69 

24. 41 

54. 77 

66 

81. 84. 93 

51. 5.V-.57, 58 



69 

29. 42. 45, 76 

75 

77, 81. 84 

3 

5 

44 

3 

5 

87 

88. 89 

88, 89 

6 



Glass, microscopic 

,, volcanic . . 
Glauconite 
Globiocephalus meloJi 
Gold 23, 38, 52, 60, 61, 82, 83, 84, 90, 91 

,, output of . . 
Goose-neck of retort 
Gordon, H. A. . . 
Ciorse . . 
(lossan.. .. .. 81, 82, 84 

Gouge . . 
(Granitic rocks . . 

,, occurrence in North Island . 

(iranophyro 
(iranulitic structure 

Grauwackes . . 20. 21. 41. 43. 44 

Gravels 7, 8, 9, 10, 21, 29, 59 

(;reensauds 20, 21, 37, 46, 47. 48, 49. .53. 
58, 61 
fossils of 
Griffiths, .\. P. .. 



14. 



)0. 66, 67, 70. 73. 74. 



(Jrits .. 

( iroundmass 

t iullics, flora of 

( iuniHclds 

( !uMi land, tlora of 

scenery of 
soil, analysis . . 
., .. treatment of 



H. 

Iliiken iincnlitris 
l/dlorayiM Utrtigynu 
11 untiles 
Hangehange 
Hanging-wall 
llaploceriUida 
Hapuka 

Hare Brothers . . 
Croek 

.. .1. 

., -Raljcn claim and (-oinpany 



Page 

67, 73 

73 

. 54 

17 

92, 93 

96, 99 

88 

14 

5 

85, 94 

80 

48, 50 

50 

50 

50 

50, 93 

61, 62 

54, 55, 

57, 58 
18, 88 
47, 59 

76. 78 

5 

16, 66 

4 

II 

. 7. 8 

. 9. 10 



4 

57 

5 

81. 83, 84, 93 

56 

17 

87 

81, 83. 84, 86 

18, 48, 53 

18,52,81,82- 

84, 86, 87 

.. 67 



■ Haystack "" . . 
Headlands influenced by nature of rocks . . 30 
Hector, J. . . 12, 13. 46, .50, 57, 58, 66, 95 

Uemiphnga novm-zelandia . . . . 3 

Heron, blue . . . . . . 3 

Htxaconilla . . . . . . . . 56 

Hexagonal jointing . . . . . . 70 

Hohoura . . . . 42. 46 

Hokanui Hills . . .. .. ..56 

Hokianga . . 68 

lJivisi(Mi ..1,2 

cephalopods fro/u . . 56 

• Hole in the Wall " 3(», 65 

Hone Heke . . 15 

Horn, Cape 47, 48 

Hornblende .. .. ;5(), 67, 73, 75, 77, 78 

-andesite . . 66, 67, 75, 78 
Hot springs {xee Ohaeawai). 

Hot -spring deposits (gee alao Ohaeawai) 60, 61 

Huia (Jreek . . . . 47, 93 

Huia Hill . . . . . . 32, 72, 87 

Button, F. VV. . . . . 12, 13, 18, 58, 87 

Hyalopilitic .. .. .. 66,74 

Hyatt . . . . . . . . 57 

Hydraulic cement . . . . 97 

,. limestone . . 21 

Hydrochloric acid . . 39, 74 
Hydrogen-sidphide 34, 35. 37, 38, 39, 61, 87, 88, 90 

Hydrothermal activity . . 37^0, 88 

Hylu uureu . . . . . . . . 3 

Hypersthene . . 67, 69, 70, 76, 77, 78 

„ -andesite . . . . 66, 67, 78 



liO 



Igneous rocks 6, 20, 21, 24, 26, 41, 

61, 

,, of doubtful age 

,, resist erosion 

Ilmenite 
Incrustations 

Industries of Whangaroa Subdivision 
Inland exposure, Waipapa Series . . 
Inoceramus beds 
Insequent drainage 
Insilting by rivers 
Introduced animals 
Introduction 

Intrusive igneous rocks {see Dykes). 
Inumia Creek . . . . 49, 55, 

Ipomea palmata 

Iron-ore . . 2, 21, 23, 62, 

„ -oxide 

„ -pyrites {see Pyxite). 
" Ironstone " country 

„ soil, analysis of 

„ ,, improvement of. . 

„ „ infertility of 

Iron-sulphide or disulphide {see also 
51, 52, 59, 65, 
IsIand-sheK 
Islets . . 

Iwitaua Bridge . . 
Ixerha brexioides 



Page 

42, 45, 46, 51, 

62, 63-79, 95 

63, 75-79, 93 
24, 26, 32 

.. 78 

.. 81 

15 

41 

12 

32 

29,32, 40 

3 

.. 1,2 

56, 58, 65, 67 

4 

67, 80, 93, 94 

37, 90, 92 

.. 4,6 

.. 6,7 

7 

7 

Pyrite) 

81, 83, 85, 86 

.. 29 

22, 29, 31 

.. 56 

5 



Jasiis htigelii 


17 


Jointing of Waipapa Series 


.. 42 


Jones Island 


31,48 


Juncus maritimus 


4 


Jurassic rocks . . 


.. 46 



Kaeo Survey District 
Kaeo Township 

„ gold near 

Kahawai 
Kahikatea 
Kahikatoa 
Kahoe Bridge . . 

,, Creek 
Kaikinikini Stream 
Kaikohe Hill . . 
Plain .. 
,, Township 
Kaipara Harbour 
Kairauwaru Bay 
Kaka . . 
Kaolinisation 
Karaka 
Karaui Point 
• Karioi 
Kauri . . 

„ forest 



5, 6, 14, 



Kauri forest, flora of 



K. 



Kaeo-Mangonui Road . . . . 48, 66 

Kaeo-Oliaeawai Road . . . . . . 7, 8 

Kaeo River 5, 6, 12, 26, 28, 31, 32, 46, 48, 49, 51, 

54, 75, 80, 86, 93, 96 
„ discharge, velocity, and length of 33 

„ coal from . . . . . . 12 

„ oil-shales from . . . . 13 

Kaeo Series 13, 14, 20, 21, 22, 23, 24, 27. 32, 37, 
45, 46-58, 59, 61, 66, 68, 71, 75, 
76, 78, 80, 93, 95, 96, 97 
,, structiure of . . . . . . 23 



2, 46, 49 

15,17,49,57,93 

19 

.. 17 

. . 5, 6 

3 

.. 66 

66 

76, 77 

..28,74 

.. 28 

2, 15, 17 

1 

29, 45, 64, 95, 96 

3 

.. .50 

4 

76, 78, 79, 93, 97 
.. 72 
34, 59, 87, 90, 96 
1, 4, 15, 16, 96 



Page 
5 



,, grass . . . . . . . . o 

„ -gum . . . . 1, 16, 80, 88, 96 

„ „ digging . . 15, 16, 17, 18 

„ ,, output of . . . . . . 96 

,, Timber Company . . . . . . 16 

Kawakawa coal . . . . . . 12 

Kawhia Harbour . . . . 50, 58 

Kemp, J. D. . . . . . . 60, 94 

Kerikeri, " megalithic remains " near . . 14 

Plains . . . . . . 20, 25, 26 

River . . 25, 32, 41, 44, 54, 55, 65, 70 

,, ,, discharge, velocity, and length 

of .. .. ..33 

Series 4, 20, 21, 22, 23, 24, 25, 27, 28. 32, 

36, 46, 47, 58, 59, 63, 65, 67, 

69-72, 74, 75, 76, 78, 79, 80, 87, 

94, 95, 96 

Kermadecs, granite from . . . . 50 

Kiekie . . . . . . . . 5 



Kiti Tawa Creek 

Kawi . . 

Knight's Lode . . 

Kohatu Whakangaongao 

Kohekohe 

Kokopu 

Kokowai 

Kovvhai 

Kuaka 

Kumarahou 



Stream 



45, 47, 55, 56 

3 

85,86 

15,94 

4,5 

3 

94 

4 

3 

4 



L. 



Labradorit© . . . . 67, 


70, 


74, 


76, 


77, 78 


Lacustrine deposits 


21, 


60 


62 


87-92 


Lagenophora forsteri 








4 


Lake- basin (see also Ngawha) 








71 


Lake-formation by lava-flows 








. 25 


Lands and Survey Department 








2 


Land-shells 








3 


Landslides 








32 


LandsUp Creek . . 






51, 


71, 75 


Land-surface, origin of ])resent 








. 24 


Lane and Sons' mill and ship yards 






16, 17 


Lane Creek 








47, 67 


Lajiilli 






. 


. 66 


Larks . . 








3 


Later basic volcanics 20, 21, 


23. 


25, 


27," 


28, 36, 



46, 63, 72, 74, 75, 94 
,, flora of . . . . 5 

soil of . . 6, 8, 17, 74 

Laurelia iiovm-zelandice . . . . . . 5, 6 

Lava-flows . . 20, 21, 31, 46, 63, 64, 65, 66, 

67, 68, 69, 78, 79, 93, 95 
„ modifying drainage 

Lead . . 
Lenses of ore 
Leptospermum ericoides . . 

,, scoparium 

Leucopogon fa-sciculatus . . 

,. fraseri 

Lignite 
Lime . . 

,, use in distillation of mercury 
Limestone 6, 8, 20, 21, 46, 47, 48, 49, 50, 51, 

53, 54, 97 
,, crystalline . . . . 41, 45 

Limonite ' . . 6, 64, 70, 73, 74, 81, 93, 94 

Limosa novcB-zetandim . . . . , • . 3 

Liolepisma moco . . . . . . 3 

Lit-erature on Whangaroa Subdivision 12-14 

Little Waitetera Pond . . . . 35, 90, 98 

Lizard . . . . . . . • 3 

Logs, erosive action of, on creek-beds . . 40 





.. 93 


'. 80, 


82, 83, 86 




3 




.. 3, 4 




4 




4 


'.'. 66, 


69, 71, 95 




7, 8, 10 


V 


89, 90 



Ill 



M 



Magnetite . . 70, 74, 76, 78 

Mahinepua Bay. . .. 11, 29, 46, 62 

Creek 65, 67 

Mahoe ... . . . • 5 

Mail-service . . . . . . 17 

Maire . . . . . . 6 

Mairehau 5 

Maitai Series . . . . 21, 50 

Makomako . . . . 5 

Malachite . . 80, 81, 83 

Mangakino Creek . . 44, 64, 70, 95 

Ridge ..27 

Mangakohou Greek 

Mangamuta Creek 

Manganese, coloration of 

,, -ore . . 

,, -oxide 

Manganite 

Mangapukahukahu Creek 45, 47, 50, 55 

Mangataraire Creek, Omapere Survey Dis- 
trict . . . . 6, 8, 48 

Mangataraire Creek, ^^^langa^oa Survey Dis- 
trict . . . . 66 

Mangatawai Creek .35, 46, 58, 59, 62, 70, 98 



Page 



pyroxenes by 

23, 45, 64, 80, 94, 
38. 



Manginangina 

,, Creek 

Mangonui 

,, meteorological station at 
Mangroves 
Mangro ve-s wamps 



4, 11, 29, 31, 

analysis of mud of 
insilting by 
soda-springs on 



51, 80, 81 



11, 72 



21, 
62, 73, 



Manoao 

Manuka 

Manukau formation 

Man's influence on physical features 

Maoris 

,, ownership of land by 

" Blaori Reserve " 

Marble. . 

Marcasite 

Maria Creek 

Maria van Diemen, Cape. 

Marine deposits 

Marojjiu Creek . . 

Marsden, Samuel 

Marshall, P. . . 

Matanehunehu Creek 

Matanohinohi 

Matawherohia Stream 

Maungaemiemi . . 

Maungakawakawa 

Maxwell, C. F. . . 

McKay, A. 12, 13. 14, 18 

" Megalithic remains " near Kerikeri 

Mdicyiua macrophyllus . . . . 5 

Mercuric sulphide (see Cinnabar). 

Mercury lodes and ores . . 2, 12, 18, 38, 60, 80, 

87-92 
native . . . . . . 23, 87, 90, 91 

reduction plant . . . . 18, 34, 88-90 

Meaembryanthemum anstrale . . . . 4 

Mesozoic fossils . . . . 49, 58 

„ rocks . . . . . . 21, 46 

Metacinnabarite . . 18, 87, 100 

Metalliferous solutions accompanying intru- 
sions . . . . . . . . 22 

Metals in sinter and veins . . 60, 80, 92, 93 

Methane . ." 88, 90 

Metrosideros rohusta . . 5, 6 



72 

44, 70 
42,40 

11 

4. 36 

36, 62 

9, 10 

28, 29 

37 

6, 59 

3, 27 

68, 69 

40 

94, 97 

8. 18 

92 

45. 97 
83, 87, 91, 99 

65, 67. 95 

1 

60, 62 

82 

15 

14, 42, 51, 66, 68, 72 

78 

44, 76, 77, 78 

59 

76, 77, 80, 85 

27, 74 

13 

19,21,46,66,68,72,95 

14, 15 



,, iomentosa 

Micrographic intergrowths 
Microlcena avenacea 
Microlites 



3, 6 

50 

5 

73 



Page 

4 

79, 81, 92, 93 

36, 80, 97 

iron-ore 94 

17, 18, 19 

46, 57, 68, 97 

15 

15 

15 

4, 6, 6 

7, 8, 9, 10 

23, 25, 27 

.. 54 

25, 27, 46 

57 

84 



Microtis porrifolia 

Mineralisation . . 23, 45, 78, 

Mineral oil (see Oil). 

Iblineral springs (see also Ohaeawai) 

,, action in formation of 

Mining, history of 

Miocene rocks . . . . 21, 42, 

Missionaries, Church of England 

,, Roman Catholic 

„ WesleyanJT . . 

" Mixed bush " . . 
Moisture 

Mokau-Pirau ridges 
Mollusca 
Monadnocks 

Monocotyledonous plant-remains 
Moorcroft Creek 
Morrison Creek . . . . . . 76, 77, 85, 86 

Moses Bay . . . . 23 

Mosses . . . . . . . . 5 

Motuekaiti . . 31, 42, 46, 69, 70, 72 

,, whaling-station at . . 17 

Mud-flats, tidal . . . . . . . . 32 

Mud of hot springs . . 38 

,, mangrove-swamps . . 37, 62 

Muds . . . . . . . . 21, 69 

Mudstones . . . . 66, 67 

Mugil cephalolua . . 17 

Mullet'.. .. .. .. ..17 

" Mushroom Rocks " . . . . . . 31 

Mussel . . . . . . . . 3 



N. 



Naturalised plants . . . . 6 

Necks, volcanic . . 25, 27, 69 

Neilson, N. . . . . . . 37 

Neilson's Soda Spring . . . . 36, 37, 60, 93 

Neinei . . . . . . . . . . 5 

Nelder, J. .. .. ..48, 51, 56, 57 

Nelson, Triassic boulders near . . 50 

Nepheline . . . . . . 74 

Nestor meridionalia . . . . 3 

New South Wales, colonists from . . . . 15 

Ngamokaikai Pond . . . . .34, 62 

Ngapuhi Tribe . . . . . . 15 

Ngawha beds . . . . . . 21, 58, 59 

Lake basin '-I 21, 23, 25, 28, 33, 34, 37, 58, 
59, 61, 62, 87-92, 95, 96, 98 

Settlement . . 17, 27, 28, 37, 58, 60 
„ ,, battlefield at . . . . 15 

Stream.. .. 37,46,68 

Nikau .. .. 5, 11 

Nip Creek 64, 95 

Nitric acidj . . 83 

Nitrogen 7, 8, 9, lO, 34, 35, 39, 90 

Nodules . . . . 61, 52 

North Auckland Peninsula j] .. 43 

„ Cape . . . .'J 1, 42, 46, 67, 68 

,, ,, breccia near . . . . . . 20 

Northern Minerals Company . . 18, 86 

North Head, Whangaroa Harbour . . 29 

North Island of New Zealand . . . . 50 



0. 



Oamaru formation 

Obsequent drainage 

Obsidian 

Ochre . . 

Ohaeawai Hot Springs 



. . 57 

. . 33 

20, 72, 73 

6, 60, 94 

2, 12, 13, 14, 18, 19, 

22, 28, 34, 35, 37- 

40, 87-92, 96, 97 



112 



51, 54, 77, 82, 



Ohaeawai Hot Springs, mercury-ore at 13, 
38, 59, 60, 61. 62 

,, ,, special areas at 18, 

39, 59, 60, 61, 62, 87, 88, 90, 9L 

„ -Okaihau Road 

„ Township 

Ohaputu Creek . . 
Oika Creek 
Oikura . . 
Oil 

Okahuiiga Creek 
Okaihau, iron-ore near 

,, Kerikeri Road 

,, Township 
Okamoko Bay . . 
Okokako Stream 
Okura Creek 

Older lava and clay uplands, flora of 
,, -flows {see cdso Kerikeri Series 

,, ,, scenery of 

Olearia solandri 
Oligoclase 
Olivine 

,, -basalt 

Omao Stream . . 

Omapere, Lake . . 



Page 

14, 37, 

, 87-92 

37, 38, 

92, 93 

60 

. 17 

37 



59, 61, 80, 

.. 13, 14, 

. . 15, 16, 
. . 26, 31, 



64, 67, 70, 74, 
64, 



3, 6, 11. 20, 27, 
34, 36, 62, 72 
,, ,, battlefield near 

Omapere Survey District 2, 27, 46, 48, 

Omiru Peninsula . . 43, 45, 65, 

Onekura Creek . . 
Opacite 

Opal in Wairakau and Kerikeri rocks 
Ophitic structure 
Orchids 
Oregon 
Orotere . . . . . . 27, 65, 

Orthoclase . . . . . . 50, 73, 

Oru .. 

Oruatemanu Island . . . . 3, 

Oruru Valley 

Ostrea 

Oteroa Creek . . . . . . 47, 65, 

Otui CVeek . . . . . . 66, 

Outliers 

Oxyrhitia von haasiii 



27 

96, 97 

49 

93, 94 
94 

17, 27 

33, 46 

28 

. 67 

4 

6 

11 

4 

75, 77 
77, 78 

65, 67 
33 

32, 33, 
, 74 

15 
49, 94 

94, 95 
64 
54 
23 

. 77 

4 

. 72 

67, 69 

76, 77 

5 
31, 64 
. 42 
. 57 

66, 70 

67, 68 
72, 80 
. 57 



Pa 








15, 40 


Pachycam'pyU 








.. 57 


Pacific Ocean . . 








1, 11, 2ti 


Packhorse Creek 








.54, 82 


Pagrosomus auratus 








17 


Pahuhu Creek . . 






, , 


47, 55 


Paingahuru Creek 








.. 43 


Pa Island 






30, 31, 


45, 47, 50, 58 


Pakaraka, rainfall at 








11 


Pakeretu Stream 






, . 


.. 33 


Palaeontology of Kaeo Series 




55-57 


Palaeozoic times, land 


of, north and 


east of 


subdivision 






.. 21 


Palaeozoic rocks 






.. 46 


Palliser Bay 






.. 50 


Panax lessonnii 






3 


Panning 






.. 91 


Papakanui Creek 






48, 76, 77 


Parahirahi 






.. 27 


Paranephops planifrons . . 




3 


Parataniwha 






5 


Pareora strata . . 






.. 57 


Paripawa Creek 






64, 70 


Parirengarenga Creek, 


diversion of 


16, 49 


Park, J. 






14, 50, 58 


Pamell grits 


. 




.. 


.. 67 



Paryphanta busbyi 
Patterson, G. W. S. 
Patukohatu 
Peach Island 
Peat . . 
Pelecypoda 
Peneplain 
Peneplaination . . 
Petroleum 
Pheasant, Chinese 
Phebalium nudum 
Phenocrysts 
Phormium tenax. . 
Phosphoric acid 
Pigeon 
Pigs, wild 

.. destruction of flora bv 
Pipi . . 

Pipiwharauroa . . 
Pirau Fault 
,, Ridge 



Page 

3 

18 

27, 69 

31, 65, 66, 67, 68 

59,69,71,95,96 

56, 57 

25, 46 

22, 24, 95 

. . 37, 38, 61, 96 

3 



67, 70, 73, 74, 75, 78 

4 

7. 8. 9 

3 

3 

3 

.. 62 

3 

23, 25, 32, 47 

.. 27 



Stream . . . . 23, 41, 45, 48, 53, 58, 97 

retreat of waterfall in . . 33 



44, 



Pirongia 

Pitch-coal 

Pittosporum ctassi folium . . 

Plagioclase 

Plains . . 

Plan of conducting work 

Plant remains . . 

Pliocene rocks . . 

Plugs, volcanic . . 

Pneumatophores of mangroves 

Podocarpus dacrydioides . . 

,, toifira 

Pohui . . 
Pohutukawa 
Polack, J. S. 
Polyprkm prognathus 
Pomnderris edgerleyi 

,, elliptica 

,, phyliccefolifi . . 

Ponds . . 

,, formation of 
Population and early history of subdivision 
Poro-te-Koihamo Creek . . 
Porphyria melanonotus 
Porphyrite 
" Porridge-pots " 
Post-Kaeo rocks 
,, -Miocene rocks 
,, -Waipapa rocks 
Potaetupuhi Bush 
Potasli . . 

Pre-Cretaceous rocks 
Pre-Jurassic rocks 
Prosihemadera iiooae-zelandim 
Protoxide of iron 
Psilomelane 
Pteris aquilinu . . 

Pug 

Puhipuhi . . . . , . 

Pukapuka 

Pukatea 

Pukatea Creek . . 

Pukeko 

Pukenui {see Te Ahuahu). 

Puketi .. .. .. 16,33,44,95 

Puketotara River . . . . 32, 65, 70 

,. discharge, length, and velo- 

city of ... . . 33 

Pumanawa Bay . . . . . . 68 

Pungaere .. 15,20,41,71,72,73,94,96 

,, -Kerikeri Road . . .. .. 94 

,, Stream . . . . . . 94 

Pungatere Stream . . . . . . 94 



.. 72 

95 

3 

50, 66. 73, 76 

25 

2 

66,69 

21 

25, 26, 27. 72 

4 

.. 5,6 

. . 5, 6 

. . 28 

3.6,11 

12 

.. 17 

4 

4 

4 

34-36, 37, 59, 62, 88, 98 

25,28 

15 

48 

3 

50 

38 

21 

21,88 

21 

93,94 

8, 10 

21 

46 

3 

39 

95 

4 

83 

46 

4 

5,6 

64 

3 



113 



Pupuke copper-Held 
,, River 



city of 
Puriri . . 

Piiruwiiarawhara Creek 
Piitahi Hill 

,, stre<ini-v(Mit.s oi 
Riilfje 
Piiwliarjiwhani. . . 
Puys . . 

Pyrite . . 4:{. 44 

Pyrilic smelt inj;. . 
Pyritised rock . . 
Pyroclast ics 
Pyroxene-andesite 
Pyroxenes 



I'age 
2, 13, 14, 18, 52, 76, 77, 78, 
80-87, 93 
G. 2(>, 28. 29, 32. 41, 45, 46, 48, 52, 
56. .-)9. 60. 70. 76, 80, 82, 86, 87 
discharge, length, and velo- 



33 

4, 5. 6, 89 

65 

27. 37, 72, 73. 98 

27. 73 

. . 37 

5 

20. 74. 75 

)4. 76. SO, )SI,S3, 84. 86. !)3 

..Ht). 87 

76, S5 

20, 21, 7«. 79, 93 

..78 

. . 64, 67, 76, 79 



Quail, C'alifornian . . 3 

Quartz. . 43. 44. .50, 54, 62, 67. 70, 73, 76, 79, 81. 93 
Quart zites 20, 2 1 , 4 1 , 44, 94, 97 

Quartz veins , . . 2, 45, .51 

Quicksilver (ute .Mercury). 



R. 

Raetea . . . . . . . . 42 

Railway for transporting timber 16 

Rainfall in various months II 

of Whangaroa .Subdivision .. 11 

Ranfurly Bay .. .. 31,65,68 

Rangiahua, rainfall at . . . . . . 11 

Rapids . . . . 32 

Rata . . . . . . . . 5. R 

Ratjen. C. .. .. 18,84 

Raupo . . . . . . 5, 59 

Realgar . . . . . . 92 

Recent beds .. .. 21.60-62 

Red Island ..31 

Reef Point . . . . 42 

Reefs .. .. ..22 

Regional metamorphism . . . . 45 

Resin-canals . . . . . . . . 68 

Resorption borders .. .. ..75 

Retorts . . 88, 89, 91 

Rhipidurn /Inbellifern 3 

Rhipogonnm scdiidenji . . . . . . .» 

RliombnwlKt {At he in .. .. .. 17 

Ritopdiostylis stipidd . . . . . . 5 

Rhyolite .. 27,73 

Rhyolitio land .. .. 8 

Rimu . . . . . . 5, 6 

„ ( 'reek . . . . . . 66 

Riroriro . . . . 3 

River-flats, soil of . . . . . . 8 

Road Creek . . 67. 75 

,, -metal 17,94 

Rock-arches . . . . . . .30 

„ -benches .. .. .. 29, .30, 31 

„ -lily 4 

Rotomanoao Creek 16, 49 

Hill .. .. ..72 

Rubus au-ftralis . . . . . . . . 5 

Rukuwai Creek . . . . 47, 69, 75 



S. 



Saddles, siphonal 
Sales, Township of 
dalicornia au^tralis 



56 

15,' 17,19,48,' 56, 57 

4 



Salivation 

Salt-water renders plant -food available 

Samolus repens . . 

Sand .. .. 7, 8. 9, 10, 21, 29. 51, 

„ lacustrine .. 21,. 59, 87.88 

Sandstones (>, 18. 20. 21. 46, 47, 48, 49, 51. 
.54, .55. .5(). .57. 65, 66, 69, 71, 
Scenery 

Schistosity and schistose rocks 23.41,42 

SchnapjxM- 
Scoria cones 
Sea-caves 

.. -coast. sliee|)-raising near 
Sca,sick Bay. former whaling-station 
Sedges 
.Sedimentary rocks, clfcc^t on land-fornis 

25.26,30,31, 
Septa . . 

Sequence of formations . . 
Serpentine . . . . 77, 

Serpentinisation 

Shafts .. 18,39,82,85, 

Shales 20, 2 1 , 42, 48, 49. 5 1 . 52. .55, 56, 57, 
71, 8.3, 86 
kerosene, oil, or jict I oljfcroiis 3, 

.Shallow-water deposits 
Shark Island 
,, -tooth 
Shattered rock (see Faulting). 
Sheared structure 
.Shepherd Oeek 
Sherman Creek . . 
.Shiimles 
Shi])- building 
.Shore-line of .Subdivision 

origin of 
Sievers Creek 
Siliceous deposits 

•Silicification .. 23,47, 

.Sillimanite 
.Silt 

Sinter . . 37. 38. 60. til. 87 

.Skerries 

Skey, W. .. .. 12, 

Slickensided rock 
Slickensiding 
Smith. S. P. .. 
.Snake River Plateau 

Soda-springs . . 36, 37, 

.Soil 

.. -analyses 

,, and agriculture 
Solfataric activity 
.Sollas, VV. .1. 

.Soot, treatment of. for mercury 
Soplujrii Iclrnplfr'i 
South-east trades, extension of 
Sparrows 

.Spars, former trade in . . 
Sphalerite 

Spherulitic grouping 
Spring-deposits . . 
.Springs 
Stacks 

Steamboat Springs, Nevada 
.Steam cavities . . 

-vents on Piitahi Hill 
.Stephenson Island .. 13. 29, .30, 31 

.Stibnite 
Stilbite 
Stirling Creek 
.Stock-raising 
Stones . . . . . . 7, 

,, building and cement 
,, for metalling 
St. Paul's Creek . . . . . . 47 



Page 

18,89 

10 

4 

(iO. 62 

91,92 

52, 53, 

80, 96 

II 

44, 7f) 

17 



22. 24. 



. 8, 9, 
»0. 91, 



26 
.30 
17 
17 
1 

32, 62 
56 

20,21 

81,84 
78 

86, 91 
.58, 69, 

71. 9(1 

69 

65 

. 57 

44 

. 51 

47 

16 

Ki, 17 

29-32 

24 

47,48 

68 

51,54 

44 

61, ()2 

93. 95 

3t). 31 

39. 61 

52.81 

80 

12 

72 

60, 93 

6.7,9 

. 6-10 

. (5-10 

23 

69 

!M) 

4 

II 

3 

.15, 16 

93 

75 

21 

36^0 

31 

87 

70, 74 

27, 73 

, 42, 64 

87.92 

78 

52 

16, 17 

i, 9, 10 

80,97 

17 

48. 51 



114 



Page 
St. Paul's Hill .. ..23,26,51,65,07,69,71 

St. Peter's Hill ■ ■ \^ . ■ ■ . . 26, 48, 65, 68 

Structure of formations" . . 22, 23, 42, 43, 47, 48,49 
Sugarloaf . . . . . . 78, 79, 93, 97 

Sulphides {see Iron, Mercury, &c). 
Sulphur 9, 23, 61, 62, 80, 83, 85, 87, 91, 96, 98 

„ corrodes retorts . . . . . . 89 

„ -springs . . . . 36, 37 

Pond, Upper . . . . . . 93 

Sulphuretted hydrogen {see Hydrogen-sulphide). 
Swamps 3, 21, 32, 36, 58, 60, 62. 71, 94, 95, 96 

„ vegetation of . . . . . . 4 

Sydney . . . . . . . . 84 

Syenite . . . . . . . . 77 

Synclines . . . . . . . . 42 



Tableland 

Takakuri Stream 
Takapuwahia 
Takitumu Hill . . 
Takou River 
Tame Pureha Creek 
Tangaire Bay 

,, Stream 

Tangitu Creek . . 
Tanks . . 
Tar . . 

Tarahi Hill and Ridge 
Taraire 

Tararu Point, Thames 
Taratara 



24, 25, 26, 27, 87, 94 

26, 28, 46 

. . 23, 70, 71, 72 

. . 76 

32, 51, 52, 75, 76 

45 

29, 62 

29, 64 

. . 29, 45, 60, 64 

88, 89 

.. 61 

. . 27, 28, 58, 74 

4, 5, 6 

. . 46 

26, 65, 69 



Taupo Bay 11, 26, 28, 29, 30, 42, 44, 45, 47, 50, 
58, 62, 65, 66, 76, 77 

Creek .. .. 28,76 

Taupuke Point . . . . ... - .76, 77 

Tauranga Bay . . 11, 23, 26, 28, 29, 42, 45, 46, 62 

Stream . . 6, 28, 62, 65, 66, 68 

Tawa . . . . . . . . 5 

Tawiri . . . . . . 5 

TeAhuahuHill .. 11,17,20,27,28,74,75 

Te Anau Series . . . . . . . . 21 

Tectonic movements . . . . . . 24 

Tehe o Riri . . . . . . 27, 69 

Te Karu Creek . . . . . . . . 48 

Telephonic communication . . . . 17 

Temperature, high, at mercury-workings . .91, 92 
,, observations at Waimate North 10 

„ of springs . . . . 37-39 

Te Patoa Creek . . . . 18, 56, 86 

Te Pukoro Stream . . . . . . 37 

Te Puru . . . . . . 23, 33 

Te Rangi HiU . . . . . . . . 72 

Terraces . . . . . . 21, 59, 62 

„ made by Maoris . . . . 40 

Tertiary fossils . . . . . . . . 49 

„ rocks . . . . . . 21, 58, 72 

Te Ruatoa Stream . . . . . . 33 

Thames . . . . . . . . 46 

Theca . . . . . . . . . . 56 

Thdymitra longifolia . . . . . . 4 

Therapeutic waters . . . . . . 97 

Thomas, A. P. W. . . . . ... 50 

Thursday Creek. . .. .. ..52 

Thrushes . . . . . . . . 3 

Ti .. .. .. .. .. 5 

Tidal channels . . . . . . 32 

„ flats . . . . . . 60, 62 

,, marsh . . . . . . . . 32 

Tides, rise and fall of . . . . . . 32 

Timber and flax industry . . 16, 32 

Toe-kiwi . . . . . . . . 5 

Tokatea Hill Series . . . . . . 46 

Totara . . . . . . . . 5, 6 



Totara North Road 

,, North Township 
Towai Settlement 
,, Stream . . 
Tracheids 
Trachyte-breccia formation 



Page 

. . 66 

15, 16, 17, 26, 65, 67 

55 

49, 55, 65 

. . 68 

.. 21 



Traction-engines for transporting timber . . 16 
Tree-ferns . . . . . . . . 5, 11 

Tregear, E. . . . . . . 14, 15 

Trenches (Maori) . . . . . . 40 

Triassic rocks . . . . . . 21, 46, 50 

Trichites . . . . . . 67 

Trigonia . . . . . . . . 56 

Trigonometrical Station A . . 27, 72 

H . . 27, 72, 94 

J3 .. ..94 

M .. ..53 

Trout . . . . . . . . . . 3 

Tuffs . . . . 20, 21, 31, 46, 47, 48, 50, 51, 

63, 64, 65, 66, 68, 78 
Tui .. .. .. ... .. 3 

Tupo Bay 2, 11, 26, 28, 29, 42, 44, 62, 78, 93 

Turritella ambulacrum . . . . . . 57 

Tutu . . . . . . . . . . 5, 40 

Tuwhakino Creek . . . . 35, 37 

Pond 18, 34, 35, 37, 62, 90, 93, 98 

Twinning . . 50, 64, 74 

Typha angustijolia . . . . . 5. 59 



u. 

Umbo . . 

Unconformities . . 
Unconformity in Kaeo Series 
Unio . . 
Upokorau Creek 
Upper Sulphur Pond 
Utakura River . . 



. . 56 

. . 45, 46, 47, 58 

. . 49 

56 

26, 67, 71, 75, 95 

. . 93 

6, 28, 33, 46, 48 



„ discharge, length, and velocity 

of .. .. ..33 

,, waterfall on . . . . 32 

Settlement . . . . . . 17 



Veins . . . . . . . . 92, 93 

Veinstone . . . . . . . . 93 

Velocity of nxain streams of subdivision . . 33 

Venus . . . . . . . . . . 56 

Vitex lucens . . . . . . 4, 5, 6 

Volcanic activity . . . . 22, 59, 72, 74 

,, ,, effect of , on siu-face-featirres 25 

„ rocks (see Igneous rocks). 



w. 



Wahinepua Bay . . . . 29, 46 

Waiapawa Pond . . . . . . 34 

Waiarewau Stream 41, 44, 70, 71, 72, 73, 75, 96 

Waihapa Stream . . . . 28, 48, 52 

Waiharakeke Creek . . . . . . 48 

Wailii Bay . . . . . . . . 26 

,, Creek . . . . . . . . 66 

Waihoanga Creek . . . . . . 48 

Waihou River . . . . 6, 8, 14, 19, 26 

,, ,, discharge, length, and velocity 

of .. .. ..33 

„ Settlement . . . . . . 17 

Waihuka Stream . . . . . . 77 

Waikape Creek . . . . . . 64, 93, 94 

Waikaraka Creek 6, 17, 29, 48. 53, 59. 97 



115 



Page 






Page 


Waikare Creek . . . . . . 47, 93 


Waterfall on Pirau Creek, retreat of 


.. 33 


Waikoura Creek . . 47, 54, 76, 87, 93 


Waterfalls 


32 


• „ mud-flat . . . . 36, 60 


Weasels 


3 


,, soda-spring . . . . 36, 93 


Whakanekeneke River . . 28, 29. 


45, 46, .53, 


Waikuku Creek . . . . . . 48 


59. 64, 70. 71 


Waimangu " geyser " . . . . . . 33 


Wliakarara 


27. 44 


Waimate North 10, 12, 13, 15, 17, 23, 25, 27, 70, 71 


Whakateterekia River . . 28, 44, 


45, 47, 54, 


,, - Okaihau Road . . . . 53 


58, 64, 76, 77 


VVaiiainuti 27, 74 


Whales and whaling 


17, 32 


Wainui Bay 29. 43, 62 


Whangarei 


.. 68 


„ Creek . . . . . . 42, 43, 65 


Whangaroa Amalgamated Claim and Co 


. 


Waionepu Creek . . 57, 67, 75 


18, 52, 77, 81, 84 


85, 86, 87 


Waipahihi Creek . . . . . . 47 


Fault 


23, 47, 69 


Waipapa River 5, 20, 28, 32, 41, 45, 64. 93, 94, 95 


Harbour 2, 11, 12, 15. 16, 


17, 23, 26, 


Series 20,21,22,23,24,26,27,32,41- 


28, 29, 31. 32, 


33, 36, 40, 


46, 47, 48, 49, 58. 61, 63-65, 


45. 47, 48. 50, 


51, 56, 58, 


68, 76, 78, 93, 94, 96, 97 


62, 65, 67, 68, 


69, 97 


Waiparaheka Pond . . 34, 35, 62, 98 


Heads 17, 28, 30. 42. 65. 


66, 76, 94 


Waipekekahau Stream . . . . 70, 71 


Survey District 


. 2, 


46. 49. 66 


VVairakau Creek . . . . 66, 67, 68. 69 


,, Township 


. 17, 


48, 51, 65 


Wairakau Series 20, 21, 22, 23, 24, 25, 26. 27. 


Whataipu Creek 




.. 70 


30.31,32,42,46,48,51.63, 


Whau .. 




4 


65-69, 72, 75. 78, 79 


„ Hill 




6. 7, 15 


Wairoa Series . . . . . . 21 


Whitehead Creek 




.. 93 


Wairoro Stream . . . . 33 


Wild-duck 




3 


Waitangi Fault . . . . 23, 25, 47 


Willis Creek 




54 


River 2, 5, 23, 25, 26, 28, 32, 47, 48. 


Willow 




5 


49. 52. 53. 54, 61. 70, 74, 97 


Winds, prevailing 




11 


discharge, length, and velo- 


,, reasserting action of 




62 


city of . . 33 


Wineberry 




5 


Waitapu Bay 48, 56, 66 . 


Winze . . 




.. 86 


Stream 28, 49 


Wood-ashes used in purifying mercury 


89 


Waitaruke Creek . . 76, 77 


Wood opal 


.. 68 


Waitemanu Creek . . . . 71 






Waitetera Pond. . . . 35, 37, 62, 87, 90, 98 






Little 35, 90, 98 






Waitetoki Creek . . . . 51 


z. 




" War in the North " . . . . 15 






Water causes precipitation of mercury . . 88 


Zeolite 


78 


Watercress . . . . 5 


Zoisite 




44 



By Authority : John Mackay, Government Printer, Wellington.— 1909. 



[7011/5/09—4832 



7516 




University of 
Connecticut 

Libraries 



39153028615625